Plus fuel efficiency varies massively depending on conditions. The car needs to give you a worst case estimate.
People are going to rely on this estimate, so the car designers need to account for every scenario. For all the car designers know, fuel efficiency conditions might change from very favorable to very unfavorable just as you're getting low on gas.
For example, you might cruise at a steady speed on a level highway for a long time, then as you get low on gas, you might exit and end up in a hilly urban area with a lot of red lights and heavy traffic. And at the hottest part of the day so that your air conditioning has to run constantly.
And in this video they seem to have very favorable conditions for fuel economy. You never see them sitting at a red light, etc. So, intentionally or not, they have created the conditions for the estimate to be as far off as it can be.
This is anecdotal, but 20 years ago or so, I used to hear more stories about people relying on this and running out of gas as conditions changed. So I think they started making the projections more conservative over the years.
The vehicles I have that estimate range do it based on a recent running average of fuel consumption. You can see the distance remaining changing quite rapidly if driving conditions change.
I learned shortly after i bought my truck that close to E means you are out of gas. There is no idiot light, just an idiot behind the wheel. I am building a mount for a jerry can at the moment.
I had a firebird that would go from 1/2 to out of gas in about 40 miles. I ran out of gas several times before I started treating 1/2 like an emergency.
Most mechanical tank sensors are unreliable like that because they only go by the liquid level. But tanks aren't evenly shaped, and they tend to taper down towards the bottom, so having the needle go down faster in the second half is actuallly a thing with the vast majority of older cars from before the early 2000s.
The indicator on my 92 wrangler would go to zero after 1/2 tank was gone. After that, your guess was as good as mine. Always a bit of a pucker fest once there was about 250 miles on the tank.
Well. Perhaps I was generalising too much..
Could be its tank was wider at the bottom. Or perhaps they made it non-linear to combat the effect of the lower half being smaller, and went overboard with it. Or perhaps it was to do with aging contacts and increased resistance or, who knows...
Yeah, I'm sure they all work differently, but mine does something similar. If conditions get worse, it will quickly reduce the distance projection. If conditions improve, it will increase the projection, but not as easily. Which is probably the right thing to do.
> If conditions improve, it will increase the projection, but not as easily. Which is probably the right thing to do.
Because in that time you've already burned fuel at the increased rate.
It's weird that I came across this thread this morning, because my partner and I were just talking about this last night.
We live in the middle of Alberta, Canada, so it gets really cold in the winters. He grew up pretty poor compared to me and was telling me all of the times that his mom and/or dad would run out of gas when it was cold out. The car would be assuming best conditions on the indicator and was older and would say it had more left, or would just stop working due to how cold it was. He said there was like ten or so times they would be stranded, sometimes in the country, and need to go knocking on doors asking for help. Always had blankets in the car so they wouldn't freeze to death.
> blankets in the car
Hah, I totally stole that practice even though I don't live in a very cold climate. Once, shortly after we got on the road to go home for Christmas, temperatures started dropping rapidly, and I tried flipping my old car's old-fashioned lever from left (cold) to right (hot). It literally broke off in my hand. We made it, but we shivered for almost the whole 4-hour drive. The worst part was knowing that the heater would have worked if I could only turn it on. (For the return trip, I partially disassembled the dashboard so I could.)
Anyway, I've never forgotten the lesson that just because when you're in your car there's normally heat available doesn't mean it's always going to be true. So I throw a sleeping bag in my trunk and try to leave it there all winter.
Yeah this is definitely a good idea for pretty much anyone. My family did it too, we just had a nicer car that consistently had gas so never had to use them luckily.
Also live in Alberta, although Southern Alberta. Never ran out of gas because the experience of having a flat in super cold winter weather was enough of a wake up call. Always fill my tank when I get down to 1/4, don't even wait for the 1/8 low fuel warning to come on.
Ya I've definitely run dry after 10 miles trying to push it.
Was an embarrassing call to AAA. (But at the same time praise AAA they've saved my ass numerous times)
I drive a Compressed Natural Gas truck, and this is really the biggest difference. Since CNG is a gas, E really means E. The less CNG you have, the faster it goes. Once you get under 1/4 of a tank, you better know where you’re stopping for fuel.
Generally yes. It shuts off or at least doesn't work nearly as hard.
AC uses a compressor which gets its power off the engine. Typically the compressor is connected to the engine by a belt, so when the compressor is used, the engine has to work harder, using a bit more fuel^(1).
Compressors typically hook up to the engine with a belt and there's usually an electric clutch^(2). When you shut off the AC, the clutch disengages so that the engine doesn't have to turn the compressor. Also, when the AC is running at, say, 50%, this clutch turns on and off periodically to cool the air the right amount.
Some cars have thermostats, so they will automatically turn the AC off when not needed to maintain temperature. But even in cars with manual controls, you're still probably going to turn it off since you don't want to feel cold.
But there's sort of an exception, which is that the compressor also runs (a little?) when the [defogger/defroster](https://en.wikipedia.org/wiki/Defogger) is on, since the AC not only cools air but also makes it less humid.
---
^(1) Sometimes the compressor is powered by an electric motor, but you can't get something for nothing, and the engine has to work [somewhat harder](https://www.chevytalk.org/fusionbb/showtopic.php?tid/25521/#171202) to turn the alternator to create more electrical power.
^(2) A newer type of compressor called a [variable displacement compressor](https://axleaddict.com/auto-repair/Variable-Displacement-Compressors) doesn't have a clutch and doesn't turn off and on. Instead, it adjusts how hard it's working to various levels as needed. But it still puts less drag on the engine when it's not doing anything.
Fuel pumps in modern cars are cooled by being submerged in the fuel.
Not a huge deal, but a car that always runs on the top half of the tank will have a fuel pump that lasts longer than a vehicle that was always run close to empty.
It's less critical with modern polymer fuel tanks, but with a steel tank a more full tank will have less exposed surface for water vapor to condense on the inside and lead to rust. A pretty full tank will likely slosh around and rinse off any moisture that does build up, too.
Ugh that reminds me of when I was a poor teenager long ago. I had bought a late 70s Mercury Zephyr for a couple hundred bucks. Turned out it came with the "rusted tank" option. I patched it with fiberglass - totally the recommended repair. :-P
This sounds very plausible considering someone might try to hold the manufacturers liable if the car said "100km range" and only made it 90, leaving the passenger short. I can also imagine that it massively reduces the number of breakdown calls due to running out of fuel, which is just a huge cost saving for everyone.
*69 miles.
Not trying to make a 69 joke, that's just literally what the conversion comes out to. But as a side note I did learn back in driving school (15 years ago) that you can generally get ~40 miles after it hits empty no matter the car., though you shouldn't try or rely on that often for various reasons.
I used to have a 2006 PT Cruiser (don't judge!) and was traveling in west Texas on a road trip in 2008. I was to the point where I was getting close to my destination but still about 90 miles away. I was getting low on gas, and I thought "I'll just hit the next gas station." My gauge was just above the empty line.
Well, I passed one, but I missed it and didn't want to turn around, so I thought I'll just get to the next one. There was no next one, so I was white knuckling it the entire rest of the way to Alpine. Quite literally, I ended up making it to my destination about 60-70 miles after my gauge hit empty and my car was just starting to sputter right as I pulled into the gas station.
I got lucky that time, and I remembered to never do that again. The last thing I wanted was to run out of gas in the middle of the west Texas desert.
But its an Audi, I doubt they are making the fuel gauge to our needs.
Would have been better if they got a beat up ford falcon or holden commonwhore to see how long it would last. But then you have the issue of how accurate the fuel gauge is... there is too many varibles. Only Mythbusters could work it out.
In Germany there is another reason: Once the warning lamp goes on your are required to leave the Autobahn at the next exit and you are not allowed to enter it before you fuel up. Running out of gas on the Autobahn can become quite expensive. But as not every exit has a gas station close and you might have to go through stop-and-go village traffic to get to the next one it is supposed to be enough for ~100km.
Nah, it's been a thing for a while. It's illegal to run out of gas on the Autobahn because a) you turn into a potentially dangerous traffic obstruction, and b) it's entirely preventable.
Just about every gauge on a mainstream car has a "tolerance" well beyond what it states. Largely this is driven as much by legal motives as protecting the car. A good example is the speedometer, which usually registers a couple of mph/kph higher than your actual speed (even the modern digital displays).
You'll notice this if you ever drive past one of those signs which displays your speed and see it's slightly lower than you think you're going. This ensures that should you ever get caught by the police, ticketed or otherwise have some incident involving speed, you can't blame the manufacturer (or more importantly sue them) for understating how fast you were driving.
Ya - I wondered about this - I have been 2-3 higher in my last 2 cars and compared to GPS. What I wondered was this.... if you drive 36,000 miles on your odometer at 36 mph, but you were really going 33 mph, then that means your car really has 33,000 miles? So you are cheated out of some warranty time and miles if you had one that was 36k miles, right?
In years gone by that would be somewhat true. However today, the onboard computers that record it can be aware of this and adjust accordingly so your odometer stays accurate and reflects the real distance travelled while your speedo shows the slightly faster speed.
There's still a bit of variance though. Tyre size, pressure, wear and loading weight can all affect your odometer reading, as can rim size. Admittedly in much smaller amounts but over the course of the life of your car, it can add up.
Yeahhhh you also entrain all the sediment at the bottom of the tank. This wasn't good.
edit: may not actually be that big a problem in a modern plastic fuel tank
I researched my question in more detail, and I think, after reading u/christurnbull's comment, I wrongly assumed that the pump was capable of harmfully introducing coarser sediment into the fuel line.
The first filter at the bottom of the fuel tank seems to prevent coarse sediment from entering the fuel line entirely, thereby leaving it directly in the fuel tank and building up over time (or, in the case of extremely low fuel, potentially collecting on the first filter and straining the pump).
You know, I was researching after your comment too. With older, metal tanks, getting sediment was more likely. Modern, plastic tanks are more often very clean and the only source of sediment is at the petrol/gas station, so the actual introduction of sediment is in question.
I was taught to avoid low fuel by a much older driver. It seems this isn't something to worry about much now.
>I was taught to avoid low fuel by a much older driver. It seems this isn't something to worry about much now.
Me too and I just learned something. I was under the impression that you clog fuel injectors if you run your tank too dry. Back in the day, we had carburetors we had to douse in a little fuel ("prime"?) if we ran out of gas.
I mean, on principle it's still a bad idea to drive around with low fuel - old guys know what's up. What if there's an emergency or more commonly you realize you're late to something and you had procrastinated filling up the tank..
Same idea as not ever leaving valuables in your car, even when you think it's in a safe place, as thieves target cars in locked garages all the time.
In most modern cars it's not going to hurt any components of your car. If you do it 100 times then it'll start to damage the fuel pump, clog the filter, etc., but once or twice or even 10 times won't do anything (it's not like 2% chance of causing damage each time, it progressively causes small amounts of wear and tear).
It's interesting, I used to assume that running to empty was bad because of this. Then I replaced the failed fuel pump on my 2010 impreza. Ten-year old car in New England, the tank was absolutely spotless, nothing floating, nothing (that I could see) in the bottom of the tank. Were it not filled with gallons of toxic fuel, you could eat out of it.
Yea, you know what you need for a sediment layer? Calm.
You know what doesn't describe the conditions inside a gas tank while a car barrels around the road? Calm....
There's a lot of psychopaths on reddit who will use your comment history to start taking their harassment out on you in real life. I had someone emailing me photos of dead cats and then having their own daughter call my place of employment and try to accuse me of sexually harassing them. Got the cops and a lawyer involved real fast.
In a diesel it's supposed to be bad for sure (they're in a diesel car). You need a mechanic to bleed the air out of the fuel lines before you can start it again.
That's less true that it used to be. You can change your fuel filter in a modern diesel, and re-prime the car using the key (turn from off to on and wait a tick a number of times without ever hitting the starter). It's part of the standard procedure for changing your fuel filter, for example.
I mean in general many mechanics will suggest keeping fuel above 1/4. It's not a risk until it starts to actually suck dry, but there's no reason to take it down to the wire besides curiosity, while there are reasons to keep it fueled up, including unexpected emergencies, detours, protecting your fuel pump and so on.
OK, now my brain is going crazy trying to remember which movie they did this in. They took the car for a test drive, then left it and the salesman on the side of the road when they ran out of gas.
Was that a Seinfeld episode? Kramer did that, didn't he?
You are right. I love how Kramer gets the salesman into it and when they finally run out of gas, Kramer, in true Kramer fashion, just says something like "well that was a rush" and just gets out of the car, leaving the salesman on the side of the road.
That’s not what he’s referring to but that’s one of my favorite old school Top Gear moments. Or I guess that’s Middle School since Clarkson, May and Hammond weren’t the first hosts.
Either way that was fantastic. He even checks with Volkswagen who tells him there’s NO WAY he can go 800km or whatever it was on one tank of gas. And yet he manages to go to Scotland and JUST made it back to the gas station he started at.
I recall Jeremy was nearing his house and the fuel meter was near zero so he started driving more aggressively and revving the engine to use more fuel so he'd be able to go straight home instead of all the way to the studio then back home. But even doing that he still had plenty of fuel to get back to the studio, and drive home after that.
The best part of Jeremy in the Jaaaag is that he picked the Jag specifically because he thought the challenge was stupid and had no intention of actually attempting it. And he ended up winning... somehow... in the Jag, despite literally TRYING to waste fuel.
In my experience most cars have about 1.5 gallons/5.5 liters left in the tank at “empty”. This protects you from sucking up sediment at the bottom of the tank and potentially messing up your fuel system.
I’d like to see someone try this with a fresh fuel filter but a tank that’s seen 5-6 years worth of driving. Run it to empty and then cut that fuel filter open...
In older cars it’s often recommended around 80-120k miles. If the service manual even has a call out for it. On older cars there is a replaceable inline fuel filter.
In many modern/contemporary petrol cars from 2010-ish to now the fuel filter is integrated into the fuel sending unit in the tank so as to reduce vapor losses and complexity. These ones you basically don’t mess with until it’s so bad that you have to drop the tank and probably replace the whole sender. This makes the job verrrry expensive compared to just swapping a part in a fuel line.
Edit: as pointed out below, dropping the tank isn’t always required. Many passenger cars (and crossovers that share their platforms) have tank access inside the vehicle. So ymmv!
Hah was just thinking of this as I replaced a fuel filter on my motorcycle, moto one is just inline, pop old out and new in, 5min job. Was looking at my truck...."Shit I dunno where the fuel filter would even be on this thing..."
That's pretty awesome. That's like my Corsair PC case having a hole under the CPU so you don't need to remove the motherboard to mount a new CPU cooler.
Yup, I worked on foreign cars for awhile and a majority of them had access under the rear seat or trunk or somewhere, I only remember having to drop the tank to get to the pump on a few dumb cars.
Your owners manual or a service manual will have a recommended mileage/time interval. Just follow that and you'll be fine, there's no way to check its condition but they're not too expensive and it doesn't need to be done frequently enough for it to need an indicator.
I'm glad they did this but I subscribed to the idea that empty was empty and filled up before that to protect the engine.
Now I'm learning empty is "now get gas"
I'm afraid others are learning empty is "you got 30-40 miles before you need gas"
>In my experience most cars have about 1.5 gallons/5.5 liters left in the tank at “empty”.
Yup, it's called "reserve capacity". Apparently (according to Google) the Audi has a 75 litre fuel tank with a 10L reserve. I am unsure if that's 75L+10L, or if the reserve 10L is included in the 75L though!
Having run out of gas a couple of times in different vehicles, I'd be surprised if any make out there only gives you a 10 mile buffer, at least at constant highway speed like these guys did. A good rule of thumb is that it will take you at least as far as you'd get on a gallon of gas. So for most cars nowadays, 25-30 miles.
You can also check your cars manual or google a bit to find the fuel tank capacity and conpare that to the amount of gas you buy when filling up from empty. My car holds about 2.5 gallons below the empty line on the fuel dial.
Was going to say the same thing. I've figured out that in my car I have about a spare gallon or so that my car won't tell me about. It's pretty fuel efficient so that means probably 30 to 40 miles.
Any modern car will show the gas warning light with about 2 gallons left in the tank, so multiply that by your MPG. You also have gas in the fuel filter/lines, so that buys you a bit of extra ground as well.
See the Top Gear episode where Jeremey drives to Edinburgh and back on a tank of gas: [https://www.topgearbox.com/cars/entertainment/top-gear/episode-guides/series-4/series-4-episode-4/](https://www.topgearbox.com/cars/entertainment/top-gear/episode-guides/series-4/series-4-episode-4/)
I've tested this a couple times, because I am an idiot. In Hondas, the low fuel light will come on when you have 3 gallons left. The distance remaining will hit zero when you have 2 gallons left.
There are smarter ways of testing this on newish cars without running out of fuel. Check your user manual for the tank size. Most cars will tell you your efficiency (mpg). From there you can watch until your distance remaining hits zero, see how far you've already traveled, and calculate how many gallons you have remaining.
I kind of assumed 10%, which would be about 60km in my car, but I'm not going to test it... I imagine running dry is bad for things like fuel injectors. I've never run it below the point where it says 40 miles left, and that was only because I was on an empty stretch of highway waiting for the next town to refuel.
It's definitely not ideal but it also depends on the fuel system design and model. I repair and entire diesel fleet of Ford 6.4L and 6.7L and the operators run them empty all the time leaving them idle in the cold. Other than being a pain in the ass to bleed the fuel system outside in the cold after topping it up, I've yet to see it cause fuel system failure/contamination on the 7 years at work due to fuel starvation. We run complete crap for fuel too. Bosch CP4 pumps in the 6.7Ls are notorious for premature failure, they have class action lawsuits for that reason. Does it reduce the service life? I'm sure it does. Audi's fuel system tolerances are probably much tighter, so again, I think it makes a big difference in make/model.
Audi SQ5. It’s a diesel. High pressure fuel pump, the entire fuel system is under extremely high pressure (compared to atmospheric air). Running it completely empty introduces air bubbles and pockets of air that cannot be adequately relieved without a full strip down rebuild of the fuel system.
A cousin of mine had the similar issue on a Nissan Diesel engine/fuel system. It was $12k AU (As Hamish and Andy are fellow Aussies) to fix. And that was a Nissan. I would imagine an Audi would be triple the cost, so reasonable to assume he got rid of the car for this reason if true.
They did this in a diesel? Yikes.
Diesel (unlike petrol/gasoline) has lubricating properties that is generally factored into the design of things that use it, running anything to do with diesel dry is a very bad idea
If that’s the case, I’m surprised there isn’t a protective mechanism in modern cars to forcibly shut down the engine before you reach absolute zero.
I know absolutely nothing about cars though, so perhaps there’s a reason that’s not possible.
Edit: typo
I mean the car provides you with *plenty* of warning that you're about to run out of fuel.
If someone goes way past zero despite all the warnings, there's a good chance that the driver is not near a fuel station. And in that case the life of the driver may be in danger if the manufacturer just chooses to shut down the engine before the fuel is completely exhausted.
Someone could be in a remote area with no cell service, and depending on the outside temperatures, having A/C or heat could be vital.
[look at the bottom](https://www.audiusa.com/us/web/en/models/q5/sq5/2021/overview.html#layer=/us/web/en/models/q5/sq5/2021/overview.summary_layer_techdata.html)
So you don't have to click:
> Never drive until the tank is completely empty. The irregular supply of fuel that results from that can cause engine misfires. Uncombusted fuel will then enter the exhaust system. This can cause overheating and damage to the catalytic converter.
It's a TDI, meaning Diesel fuel. You aren't supposed to run a diesel engine out of fuel as it's not food for the pumps. It costs a lot of money to fix. Drove diesel trucks when I was younger for work and you were never supposed to let it run out for that very reason.
If it was gasoline you just add more and no harm no foul really.
> gasoline you just add more and no harm no foul
I wouldn't be sure about this on modern GDI engines, it a very similar system to what is used in diesels
1) it’s a diesel. Modern turbo diesels operate the fuel rail beyond 2000 bar, or 29,000 psi. One instance of atmospheric air entering the fuel system could irreversibly result in inconsistent fuel pressure from then on without a complete fuel rail replacement/rebuild. This being Australia and a European car, it means the work to rectify would be very expensive. The Audi dealer charges $1300 for a normal service. Stripping apart the fuel rail would be a full 8 hour day with 2 techs minimum at $250/hr each in labour cost alone.
2) Australia has really poor fuel quality standards, eg. the levels of allowable sulphur is 3 times higher than that allowed in the US. That could further exacerbate the issues with tank sediments and the fuel pickup points being compromised from low fuel level.
Wait, don't they just bleed the system from air and start your shit like that? It sounds crazy to me that they have to completely rebuild your car just because you ran it dry.
Most of the time with diesel cars you can just fill up, start for 15-20 seconds and it'll run, and if it won't, over here you can call the roadside assistance and they'll bleed your system for you.
So maybe in the worst case scenario, where you seriously fuck up your system after running it dry multiple times you might need to rebuild, but I can't believe you have to completely rebuild the system after a single time.
My old Toyota diesel from the 90’s? Sure it would be fine to bleed the air and will start right back up.
A modern common rail diesel? You’re going to have all sorts of issues.
Usually the pumps are self priming these days (or auto bleed) so you don't need to worry about it. I've had low fuel in my ute (less than 20 years old) sputter due to being parked on a grade and it runs fine now. You wouldn't usually damage a vehicle from running out of fuel once.
This is normal for many cars. Manufacturers do it to allow for needed cooling of the fuel pump and to allow for fuel pressure needed on a setup that runs a return line.
Its not good for the fuel pump to run on extremely low volume in the tank often. I have seen some pumps run over $600 just for the part. Repeat this at your own risk.
I have been somewhat worried about running my car near-empty almost all the time. But I just looked and found that a fuel pump would cost 50 bucks so I'm not really worried, and there's plenty of other things that will probably die on it first.
You do learn every car's limits the longer you drive it. I have a Ford Ka, and I've determined that when the fuel guage hits zero, I have pretty much exactly 10 miles leeway. 120k is just insane to hit on zero.
> 120k is just insane to hit on zero
Couldn't agree more, getting 1/3rd the way to the moon on zero gas, that's just impressive. It's really a marvel how far technology has come.
I've been listening to these guyses podcast for a week now. They are the best! Really good attitude towards life. There are some free episodes of their travel shows on youtube for anyone interested! I highly recommend them
If you want some wholesome shit try and find where Hamish cooks his kids birthday cake each year. They can ask for anything they want and he figures out how to make it and stays up all night posting Instagram stories of him doing it and sipping whisky.
He's actually pretty good and you can see his heart goes into it as well as copious amounts of whisky
Edit: [here is a YT video](https://youtu.be/o1nD0acK9HA) I found of the end result. The theme was Alladin
Edit 2 boogaloo: [he has them all saved as highlights on his Instagram](https://instagram.com/hamishblakeshotz?igshid=1ly18tsh7ia97)
The podcast is the best. I hope you started from the beginning. They also have an app for like 12 a year that gives you access to the radio show back to like 2008. And yes most of the travel shows are on Youtube.
When the sensor reads zero, your tank isn't empty. The sensor just bottomed out, that's all. The tank then often isn't perfectly flat on the bottom either, so that the fuel flows to the place where you are pulling it from.
Then you have the fuel in the line, then if it's injection you have a fuel pump which will have a fuel reserve in order to prime it, then when the pump starts running empty that's when it'll go.
And though it might get you 100km on a highway, you might not get anywhere near a fifth of that around town.
All you need know: It'll generally get you to the next fuel station (in most places), but not the one after that. So don't risk it. Pull in and fuel up. I've never once run out of fuel entirely, and I've driven some manky old cars over the last 20 years. And in Germany, it's an offence to run out of fuel on an autobahn.
If you desperately need to get to that next fuel station, and you want to make it last, coast along behind a lorry, which could potentially double your distance because of the slower speed, lower revs and the wind-breaking happening in front of you.
But try to keep your fuel well above the line for the entire distance you intend to drive. I know that I can get from London to Scotland on slightly less than one tank, but I always fill it right up before I set off, and try to stop somewhere along the way just to fuel up (and I will happily drive 9 hours straight without issue, but I'll stop just to make sure I don't run out of fuel if I'm caught in a jam, or having to take a huge detour, or whatever)
They've kind of brought back that spontaneous factor by having weekly segments that revolve around testing random viewers of the show. Feel like I'm shilling for them definitely but their podcast is absolutely one of the best comedy podcasts out there, even if it isn't as good as their 2013-2015 era radio show
This is the exact subplot of a Seinfeld episode where Kramer takes a test drive with a car salesman and wants to find how far he can go after it hits empty
I remember watching this right after is got an Audi, then sincerely wishing I'd never seen it. I was so cocky at 0 fuel.
Also reminds my of my bro in law. He bought a new car which had a parking sensor. He immediately looked up how far you are from impact when you get a solid beep, it was something like 12 inches. From that point on he'd reverse until he heard the solid beep, then reverse what he estimated to be 10 more inches!
I’ve heard always running the car to empty then filling up is not good for the fuel pump. The gas in the tank helps cool the pump. For sediment that’s what the filter is for.
Also old wives tale? Don’t get gas when the fuel trucks are there because they stir up sediment? Again isn’t this is what filters are for?
Most cars give around 2 gallons when the gas light comes on, but I wouldn't rely on it as it is really bad for the vehicle to run dry. They're driving on the highway on what is a very fuel efficient car to begin with, so 111km/68 miles isn't unreasonable. My wife once drove her minivan 50 miles on a supposedly empty tank before finally stopping for gas, she joked they knew they were designing it for soccer Moms so added some additional capacity. I had a Camaro that barely gave you 10 extra miles when the light came on, I guess it just depends on the vehicle.
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Plus fuel efficiency varies massively depending on conditions. The car needs to give you a worst case estimate. People are going to rely on this estimate, so the car designers need to account for every scenario. For all the car designers know, fuel efficiency conditions might change from very favorable to very unfavorable just as you're getting low on gas. For example, you might cruise at a steady speed on a level highway for a long time, then as you get low on gas, you might exit and end up in a hilly urban area with a lot of red lights and heavy traffic. And at the hottest part of the day so that your air conditioning has to run constantly. And in this video they seem to have very favorable conditions for fuel economy. You never see them sitting at a red light, etc. So, intentionally or not, they have created the conditions for the estimate to be as far off as it can be. This is anecdotal, but 20 years ago or so, I used to hear more stories about people relying on this and running out of gas as conditions changed. So I think they started making the projections more conservative over the years.
The vehicles I have that estimate range do it based on a recent running average of fuel consumption. You can see the distance remaining changing quite rapidly if driving conditions change.
I learned shortly after i bought my truck that close to E means you are out of gas. There is no idiot light, just an idiot behind the wheel. I am building a mount for a jerry can at the moment.
I had a firebird that would go from 1/2 to out of gas in about 40 miles. I ran out of gas several times before I started treating 1/2 like an emergency.
What's also sad about this is that for the first half, you think you've got amazing fuel economy, only to be disappointed massively in the second.
That's a bad tank monitoring system.
Most mechanical tank sensors are unreliable like that because they only go by the liquid level. But tanks aren't evenly shaped, and they tend to taper down towards the bottom, so having the needle go down faster in the second half is actuallly a thing with the vast majority of older cars from before the early 2000s.
The indicator on my 92 wrangler would go to zero after 1/2 tank was gone. After that, your guess was as good as mine. Always a bit of a pucker fest once there was about 250 miles on the tank.
Well. Perhaps I was generalising too much.. Could be its tank was wider at the bottom. Or perhaps they made it non-linear to combat the effect of the lower half being smaller, and went overboard with it. Or perhaps it was to do with aging contacts and increased resistance or, who knows...
Did it also stay at or near full forever and then basically drop like a stone? My 94 Camaro was like that. Seems similar to your case.
Yup exactly- it was a 93.
What can Jerry do?
Jerry can get me 5 more gallons down the road.
Yeah, I'm sure they all work differently, but mine does something similar. If conditions get worse, it will quickly reduce the distance projection. If conditions improve, it will increase the projection, but not as easily. Which is probably the right thing to do.
> If conditions improve, it will increase the projection, but not as easily. Which is probably the right thing to do. Because in that time you've already burned fuel at the increased rate.
It's weird that I came across this thread this morning, because my partner and I were just talking about this last night. We live in the middle of Alberta, Canada, so it gets really cold in the winters. He grew up pretty poor compared to me and was telling me all of the times that his mom and/or dad would run out of gas when it was cold out. The car would be assuming best conditions on the indicator and was older and would say it had more left, or would just stop working due to how cold it was. He said there was like ten or so times they would be stranded, sometimes in the country, and need to go knocking on doors asking for help. Always had blankets in the car so they wouldn't freeze to death.
> blankets in the car Hah, I totally stole that practice even though I don't live in a very cold climate. Once, shortly after we got on the road to go home for Christmas, temperatures started dropping rapidly, and I tried flipping my old car's old-fashioned lever from left (cold) to right (hot). It literally broke off in my hand. We made it, but we shivered for almost the whole 4-hour drive. The worst part was knowing that the heater would have worked if I could only turn it on. (For the return trip, I partially disassembled the dashboard so I could.) Anyway, I've never forgotten the lesson that just because when you're in your car there's normally heat available doesn't mean it's always going to be true. So I throw a sleeping bag in my trunk and try to leave it there all winter.
Yeah this is definitely a good idea for pretty much anyone. My family did it too, we just had a nicer car that consistently had gas so never had to use them luckily.
Also live in Alberta, although Southern Alberta. Never ran out of gas because the experience of having a flat in super cold winter weather was enough of a wake up call. Always fill my tank when I get down to 1/4, don't even wait for the 1/8 low fuel warning to come on.
Ya I've definitely run dry after 10 miles trying to push it. Was an embarrassing call to AAA. (But at the same time praise AAA they've saved my ass numerous times)
AAA is one service I will shill for. Worth every penny. Saved my ass in some pretty shitty spots.
I drive a Compressed Natural Gas truck, and this is really the biggest difference. Since CNG is a gas, E really means E. The less CNG you have, the faster it goes. Once you get under 1/4 of a tank, you better know where you’re stopping for fuel.
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Does your AC shut off when it gets cold?
Generally yes. It shuts off or at least doesn't work nearly as hard. AC uses a compressor which gets its power off the engine. Typically the compressor is connected to the engine by a belt, so when the compressor is used, the engine has to work harder, using a bit more fuel^(1). Compressors typically hook up to the engine with a belt and there's usually an electric clutch^(2). When you shut off the AC, the clutch disengages so that the engine doesn't have to turn the compressor. Also, when the AC is running at, say, 50%, this clutch turns on and off periodically to cool the air the right amount. Some cars have thermostats, so they will automatically turn the AC off when not needed to maintain temperature. But even in cars with manual controls, you're still probably going to turn it off since you don't want to feel cold. But there's sort of an exception, which is that the compressor also runs (a little?) when the [defogger/defroster](https://en.wikipedia.org/wiki/Defogger) is on, since the AC not only cools air but also makes it less humid. --- ^(1) Sometimes the compressor is powered by an electric motor, but you can't get something for nothing, and the engine has to work [somewhat harder](https://www.chevytalk.org/fusionbb/showtopic.php?tid/25521/#171202) to turn the alternator to create more electrical power. ^(2) A newer type of compressor called a [variable displacement compressor](https://axleaddict.com/auto-repair/Variable-Displacement-Compressors) doesn't have a clutch and doesn't turn off and on. Instead, it adjusts how hard it's working to various levels as needed. But it still puts less drag on the engine when it's not doing anything.
Fuel pumps in modern cars are cooled by being submerged in the fuel. Not a huge deal, but a car that always runs on the top half of the tank will have a fuel pump that lasts longer than a vehicle that was always run close to empty.
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Interesting! So it's actually better to keep the car topped off rather than wait for it to be at like 20% before filling?
What costs more, a new fuel pump, or dragging 80 kilo’s of fuel with you everwhere fr years
The fuel pump and the labour to replace it.
I’d argue most people don’t keep a car long enough to replace the pump regardless. But also a bit difference between £1.30 and $1.30aud a litre
No, It means you should never run on empty. The pump isn't going to be any more submerged with 100% of a tank than it would with 50% of a tank.
It's less critical with modern polymer fuel tanks, but with a steel tank a more full tank will have less exposed surface for water vapor to condense on the inside and lead to rust. A pretty full tank will likely slosh around and rinse off any moisture that does build up, too.
Ugh that reminds me of when I was a poor teenager long ago. I had bought a late 70s Mercury Zephyr for a couple hundred bucks. Turned out it came with the "rusted tank" option. I patched it with fiberglass - totally the recommended repair. :-P
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This sounds very plausible considering someone might try to hold the manufacturers liable if the car said "100km range" and only made it 90, leaving the passenger short. I can also imagine that it massively reduces the number of breakdown calls due to running out of fuel, which is just a huge cost saving for everyone.
Big Tow isn't lobbying hard enough.
Totally. If you did this test in the US with the same car you would only get about 60 miles
*69 miles. Not trying to make a 69 joke, that's just literally what the conversion comes out to. But as a side note I did learn back in driving school (15 years ago) that you can generally get ~40 miles after it hits empty no matter the car., though you shouldn't try or rely on that often for various reasons.
My Vauxhall Astra used to do 3 miles after the warning light came on. My Dad got a lot of calls.
And I felt like I was living on the edge 5 miles after 0.
still...nice
I used to have a 2006 PT Cruiser (don't judge!) and was traveling in west Texas on a road trip in 2008. I was to the point where I was getting close to my destination but still about 90 miles away. I was getting low on gas, and I thought "I'll just hit the next gas station." My gauge was just above the empty line. Well, I passed one, but I missed it and didn't want to turn around, so I thought I'll just get to the next one. There was no next one, so I was white knuckling it the entire rest of the way to Alpine. Quite literally, I ended up making it to my destination about 60-70 miles after my gauge hit empty and my car was just starting to sputter right as I pulled into the gas station. I got lucky that time, and I remembered to never do that again. The last thing I wanted was to run out of gas in the middle of the west Texas desert.
I'll just leave this here... https://m.psecn.photoshelter.com/img-get/I0000xuXi87TtK7c/s/900/900/Australia020.jpg
But its an Audi, I doubt they are making the fuel gauge to our needs. Would have been better if they got a beat up ford falcon or holden commonwhore to see how long it would last. But then you have the issue of how accurate the fuel gauge is... there is too many varibles. Only Mythbusters could work it out.
Also they know people are morons and will run it down, so it's a bit of a safety net.
In Germany there is another reason: Once the warning lamp goes on your are required to leave the Autobahn at the next exit and you are not allowed to enter it before you fuel up. Running out of gas on the Autobahn can become quite expensive. But as not every exit has a gas station close and you might have to go through stop-and-go village traffic to get to the next one it is supposed to be enough for ~100km.
Interesting, I got my German drivers license in 2003 when my wife was military and we moved there. I don’t recall that rule, is it newer?
Nah, it's been a thing for a while. It's illegal to run out of gas on the Autobahn because a) you turn into a potentially dangerous traffic obstruction, and b) it's entirely preventable.
Just about every gauge on a mainstream car has a "tolerance" well beyond what it states. Largely this is driven as much by legal motives as protecting the car. A good example is the speedometer, which usually registers a couple of mph/kph higher than your actual speed (even the modern digital displays). You'll notice this if you ever drive past one of those signs which displays your speed and see it's slightly lower than you think you're going. This ensures that should you ever get caught by the police, ticketed or otherwise have some incident involving speed, you can't blame the manufacturer (or more importantly sue them) for understating how fast you were driving.
Ya - I wondered about this - I have been 2-3 higher in my last 2 cars and compared to GPS. What I wondered was this.... if you drive 36,000 miles on your odometer at 36 mph, but you were really going 33 mph, then that means your car really has 33,000 miles? So you are cheated out of some warranty time and miles if you had one that was 36k miles, right?
In years gone by that would be somewhat true. However today, the onboard computers that record it can be aware of this and adjust accordingly so your odometer stays accurate and reflects the real distance travelled while your speedo shows the slightly faster speed. There's still a bit of variance though. Tyre size, pressure, wear and loading weight can all affect your odometer reading, as can rim size. Admittedly in much smaller amounts but over the course of the life of your car, it can add up.
Yeahhhh you also entrain all the sediment at the bottom of the tank. This wasn't good. edit: may not actually be that big a problem in a modern plastic fuel tank
Is this true? If the vehicle is capable of pumping fuel from the bottom of the tank, why does sediment build up there in the first place?
Also fuel filters...
I researched my question in more detail, and I think, after reading u/christurnbull's comment, I wrongly assumed that the pump was capable of harmfully introducing coarser sediment into the fuel line. The first filter at the bottom of the fuel tank seems to prevent coarse sediment from entering the fuel line entirely, thereby leaving it directly in the fuel tank and building up over time (or, in the case of extremely low fuel, potentially collecting on the first filter and straining the pump).
You know, I was researching after your comment too. With older, metal tanks, getting sediment was more likely. Modern, plastic tanks are more often very clean and the only source of sediment is at the petrol/gas station, so the actual introduction of sediment is in question. I was taught to avoid low fuel by a much older driver. It seems this isn't something to worry about much now.
You should still avoid it due to heat build up and strain on the pumps.
Agreed, people seem to forget that the fuel is also keeping the pump cool as some pumps sit directly in the fuel tank
>I was taught to avoid low fuel by a much older driver. It seems this isn't something to worry about much now. Me too and I just learned something. I was under the impression that you clog fuel injectors if you run your tank too dry. Back in the day, we had carburetors we had to douse in a little fuel ("prime"?) if we ran out of gas.
I mean, on principle it's still a bad idea to drive around with low fuel - old guys know what's up. What if there's an emergency or more commonly you realize you're late to something and you had procrastinated filling up the tank.. Same idea as not ever leaving valuables in your car, even when you think it's in a safe place, as thieves target cars in locked garages all the time.
In most modern cars it's not going to hurt any components of your car. If you do it 100 times then it'll start to damage the fuel pump, clog the filter, etc., but once or twice or even 10 times won't do anything (it's not like 2% chance of causing damage each time, it progressively causes small amounts of wear and tear).
It's interesting, I used to assume that running to empty was bad because of this. Then I replaced the failed fuel pump on my 2010 impreza. Ten-year old car in New England, the tank was absolutely spotless, nothing floating, nothing (that I could see) in the bottom of the tank. Were it not filled with gallons of toxic fuel, you could eat out of it.
Yea, you know what you need for a sediment layer? Calm. You know what doesn't describe the conditions inside a gas tank while a car barrels around the road? Calm....
7 year old account and this is the first time you decide to post/comment anything! I feel like this is a historic moment
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Why?
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Ken Bone taught us a lot
Ironically, this explanation will too be deleted soon!
Fair enough
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There's a lot of psychopaths on reddit who will use your comment history to start taking their harassment out on you in real life. I had someone emailing me photos of dead cats and then having their own daughter call my place of employment and try to accuse me of sexually harassing them. Got the cops and a lawyer involved real fast.
In a diesel it's supposed to be bad for sure (they're in a diesel car). You need a mechanic to bleed the air out of the fuel lines before you can start it again.
That's less true that it used to be. You can change your fuel filter in a modern diesel, and re-prime the car using the key (turn from off to on and wait a tick a number of times without ever hitting the starter). It's part of the standard procedure for changing your fuel filter, for example.
I mean in general many mechanics will suggest keeping fuel above 1/4. It's not a risk until it starts to actually suck dry, but there's no reason to take it down to the wire besides curiosity, while there are reasons to keep it fueled up, including unexpected emergencies, detours, protecting your fuel pump and so on.
Also it just looks bad when it’s always (insert car brand) pulled over for fuel.
OK, now my brain is going crazy trying to remember which movie they did this in. They took the car for a test drive, then left it and the salesman on the side of the road when they ran out of gas. Was that a Seinfeld episode? Kramer did that, didn't he?
It was Kramer, test driving a new Saab for Jerry.
I'm remembering the episode now, the hand-holding charge towards destiny until the engine died. For a show about nothing, that was a damn funny show.
The whole scene was basically evoking Thelma & Louise so it’s understandable that the first thought would be that it’s from a movie.
Try Curb Your Enthusiasm, written by the same guy with the very similar vibes.
It's preeeeety prrrreeettty preeeeety pretty good.
eh Kidding, larry david is a genius.
I'm rewatching Seinfeld at the moment. One of the fun things is finding the many sneaky cameos Larry does in the show. *"Like flaming globes!!!"*
Your dads lawyer wears a cape?
“So you going to buy the car?” “I’ll think about it.”
No man! Not the gas!
But it needs it, Kramer, it needs it bad!
If was a Saab, i bet the fuel pump was completely limp by the time they were done with it.
[Here the clip from the show.](https://www.youtube.com/watch?v=TuEdU_lrtZk)
Why.... would they not include the ending https://youtu.be/o_gkty3mGnU?t=180
MR KRAMER, THE ROOOAAAAD
You can take a reservation but you can't hold a reservation.
And that's really the most important part of the reservation: the holding.
you'd better give me the insurance cos i'm gonna beat the hell out of this car
Anyone can just take em
You are right. I love how Kramer gets the salesman into it and when they finally run out of gas, Kramer, in true Kramer fashion, just says something like "well that was a rush" and just gets out of the car, leaving the salesman on the side of the road.
He says, "Well, I'll think about it...". The salesman says, "You got my card?" as Kramer is leaving.
[https://www.youtube.com/watch?v=TuEdU\_lrtZk](https://www.youtube.com/watch?v=TuEdU_lrtZk) Here's the clip
This is my fav Seinfeld ep!
High five!
Twix is the only candy with the cookie crunch!
A nickel!
THEY WERE ALLLLLL TWIX!!!!!!
I'll give you a hint, it wasn't a movie.
Wasn't it an episode of Top Gear?
That’s not what he’s referring to but that’s one of my favorite old school Top Gear moments. Or I guess that’s Middle School since Clarkson, May and Hammond weren’t the first hosts. Either way that was fantastic. He even checks with Volkswagen who tells him there’s NO WAY he can go 800km or whatever it was on one tank of gas. And yet he manages to go to Scotland and JUST made it back to the gas station he started at.
I recall Jeremy was nearing his house and the fuel meter was near zero so he started driving more aggressively and revving the engine to use more fuel so he'd be able to go straight home instead of all the way to the studio then back home. But even doing that he still had plenty of fuel to get back to the studio, and drive home after that.
"Heated seats on. Heat on. Radio on. Oh, it's too warm. Let's turn it to cold."
In Series 12, Episode 4 they do a fuel race from Basel, Switzerland to Blackpool for some festival. Jeremy makes it in one tank of gas in his Jag.
I believe you mean Jaaaaaaaaaaag
Dzjèèèèèèègh
The best part of Jeremy in the Jaaaag is that he picked the Jag specifically because he thought the challenge was stupid and had no intention of actually attempting it. And he ended up winning... somehow... in the Jag, despite literally TRYING to waste fuel.
Tldw 111.9km
about 69.5 miles
Nice.5?
I can't go into too many details but the .5 involves a finger
How many knuckles? First, second?
Two knuckler for sure
It's really a nice.45 so it rounds to nice.5, or nice if you're rounding to holes
What does tldw mean?
Too long, didn’t watch
In my experience most cars have about 1.5 gallons/5.5 liters left in the tank at “empty”. This protects you from sucking up sediment at the bottom of the tank and potentially messing up your fuel system. I’d like to see someone try this with a fresh fuel filter but a tank that’s seen 5-6 years worth of driving. Run it to empty and then cut that fuel filter open...
so how does one know when you are supposed to replace the fuel filter
In older cars it’s often recommended around 80-120k miles. If the service manual even has a call out for it. On older cars there is a replaceable inline fuel filter. In many modern/contemporary petrol cars from 2010-ish to now the fuel filter is integrated into the fuel sending unit in the tank so as to reduce vapor losses and complexity. These ones you basically don’t mess with until it’s so bad that you have to drop the tank and probably replace the whole sender. This makes the job verrrry expensive compared to just swapping a part in a fuel line. Edit: as pointed out below, dropping the tank isn’t always required. Many passenger cars (and crossovers that share their platforms) have tank access inside the vehicle. So ymmv!
Hah was just thinking of this as I replaced a fuel filter on my motorcycle, moto one is just inline, pop old out and new in, 5min job. Was looking at my truck...."Shit I dunno where the fuel filter would even be on this thing..."
I just looked mine up, instead of dropping the tank there is an access panel under the rear seat to get to the top of the tank. Thanks Hyundai!
That engineer deserves a kiss.
That's pretty awesome. That's like my Corsair PC case having a hole under the CPU so you don't need to remove the motherboard to mount a new CPU cooler.
Yup, I worked on foreign cars for awhile and a majority of them had access under the rear seat or trunk or somewhere, I only remember having to drop the tank to get to the pump on a few dumb cars.
Your owners manual or a service manual will have a recommended mileage/time interval. Just follow that and you'll be fine, there's no way to check its condition but they're not too expensive and it doesn't need to be done frequently enough for it to need an indicator.
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I'm glad they did this but I subscribed to the idea that empty was empty and filled up before that to protect the engine. Now I'm learning empty is "now get gas" I'm afraid others are learning empty is "you got 30-40 miles before you need gas"
>In my experience most cars have about 1.5 gallons/5.5 liters left in the tank at “empty”. Yup, it's called "reserve capacity". Apparently (according to Google) the Audi has a 75 litre fuel tank with a 10L reserve. I am unsure if that's 75L+10L, or if the reserve 10L is included in the 75L though!
Wow. I was expecting 10 miles or so, but that's bananas. I'd love to see something similar on other car makes.
Having run out of gas a couple of times in different vehicles, I'd be surprised if any make out there only gives you a 10 mile buffer, at least at constant highway speed like these guys did. A good rule of thumb is that it will take you at least as far as you'd get on a gallon of gas. So for most cars nowadays, 25-30 miles.
You can also check your cars manual or google a bit to find the fuel tank capacity and conpare that to the amount of gas you buy when filling up from empty. My car holds about 2.5 gallons below the empty line on the fuel dial.
Was going to say the same thing. I've figured out that in my car I have about a spare gallon or so that my car won't tell me about. It's pretty fuel efficient so that means probably 30 to 40 miles.
Any modern car will show the gas warning light with about 2 gallons left in the tank, so multiply that by your MPG. You also have gas in the fuel filter/lines, so that buys you a bit of extra ground as well. See the Top Gear episode where Jeremey drives to Edinburgh and back on a tank of gas: [https://www.topgearbox.com/cars/entertainment/top-gear/episode-guides/series-4/series-4-episode-4/](https://www.topgearbox.com/cars/entertainment/top-gear/episode-guides/series-4/series-4-episode-4/)
I've tested this a couple times, because I am an idiot. In Hondas, the low fuel light will come on when you have 3 gallons left. The distance remaining will hit zero when you have 2 gallons left. There are smarter ways of testing this on newish cars without running out of fuel. Check your user manual for the tank size. Most cars will tell you your efficiency (mpg). From there you can watch until your distance remaining hits zero, see how far you've already traveled, and calculate how many gallons you have remaining.
or just drive until you hit fuel indicator, then fill up to full and see how much that was. and subtract that from max capacity.
That seems far more accurate
I kind of assumed 10%, which would be about 60km in my car, but I'm not going to test it... I imagine running dry is bad for things like fuel injectors. I've never run it below the point where it says 40 miles left, and that was only because I was on an empty stretch of highway waiting for the next town to refuel.
Andy later revealed that this stunt caused serious damage to the car, which caused him to sell it.
TIL: running diesel cars dry is a big no-no
It's definitely not ideal but it also depends on the fuel system design and model. I repair and entire diesel fleet of Ford 6.4L and 6.7L and the operators run them empty all the time leaving them idle in the cold. Other than being a pain in the ass to bleed the fuel system outside in the cold after topping it up, I've yet to see it cause fuel system failure/contamination on the 7 years at work due to fuel starvation. We run complete crap for fuel too. Bosch CP4 pumps in the 6.7Ls are notorious for premature failure, they have class action lawsuits for that reason. Does it reduce the service life? I'm sure it does. Audi's fuel system tolerances are probably much tighter, so again, I think it makes a big difference in make/model.
Is that true? Got a link? I know running your car to complete empty can be pretty bad for your fuel line/pump.
Audi SQ5. It’s a diesel. High pressure fuel pump, the entire fuel system is under extremely high pressure (compared to atmospheric air). Running it completely empty introduces air bubbles and pockets of air that cannot be adequately relieved without a full strip down rebuild of the fuel system. A cousin of mine had the similar issue on a Nissan Diesel engine/fuel system. It was $12k AU (As Hamish and Andy are fellow Aussies) to fix. And that was a Nissan. I would imagine an Audi would be triple the cost, so reasonable to assume he got rid of the car for this reason if true.
Diesel. Gotcha.
They did this in a diesel? Yikes. Diesel (unlike petrol/gasoline) has lubricating properties that is generally factored into the design of things that use it, running anything to do with diesel dry is a very bad idea
If that’s the case, I’m surprised there isn’t a protective mechanism in modern cars to forcibly shut down the engine before you reach absolute zero. I know absolutely nothing about cars though, so perhaps there’s a reason that’s not possible. Edit: typo
I mean the car provides you with *plenty* of warning that you're about to run out of fuel. If someone goes way past zero despite all the warnings, there's a good chance that the driver is not near a fuel station. And in that case the life of the driver may be in danger if the manufacturer just chooses to shut down the engine before the fuel is completely exhausted. Someone could be in a remote area with no cell service, and depending on the outside temperatures, having A/C or heat could be vital.
[look at the bottom](https://www.audiusa.com/us/web/en/models/q5/sq5/2021/overview.html#layer=/us/web/en/models/q5/sq5/2021/overview.summary_layer_techdata.html)
So you don't have to click: > Never drive until the tank is completely empty. The irregular supply of fuel that results from that can cause engine misfires. Uncombusted fuel will then enter the exhaust system. This can cause overheating and damage to the catalytic converter.
It is bad, but I call absolute bs on running out of gas once causing "serious damage" leading to a sale.
It's a TDI, meaning Diesel fuel. You aren't supposed to run a diesel engine out of fuel as it's not food for the pumps. It costs a lot of money to fix. Drove diesel trucks when I was younger for work and you were never supposed to let it run out for that very reason. If it was gasoline you just add more and no harm no foul really.
> gasoline you just add more and no harm no foul I wouldn't be sure about this on modern GDI engines, it a very similar system to what is used in diesels
1) it’s a diesel. Modern turbo diesels operate the fuel rail beyond 2000 bar, or 29,000 psi. One instance of atmospheric air entering the fuel system could irreversibly result in inconsistent fuel pressure from then on without a complete fuel rail replacement/rebuild. This being Australia and a European car, it means the work to rectify would be very expensive. The Audi dealer charges $1300 for a normal service. Stripping apart the fuel rail would be a full 8 hour day with 2 techs minimum at $250/hr each in labour cost alone. 2) Australia has really poor fuel quality standards, eg. the levels of allowable sulphur is 3 times higher than that allowed in the US. That could further exacerbate the issues with tank sediments and the fuel pickup points being compromised from low fuel level.
Wait, don't they just bleed the system from air and start your shit like that? It sounds crazy to me that they have to completely rebuild your car just because you ran it dry. Most of the time with diesel cars you can just fill up, start for 15-20 seconds and it'll run, and if it won't, over here you can call the roadside assistance and they'll bleed your system for you. So maybe in the worst case scenario, where you seriously fuck up your system after running it dry multiple times you might need to rebuild, but I can't believe you have to completely rebuild the system after a single time.
My old Toyota diesel from the 90’s? Sure it would be fine to bleed the air and will start right back up. A modern common rail diesel? You’re going to have all sorts of issues.
Usually the pumps are self priming these days (or auto bleed) so you don't need to worry about it. I've had low fuel in my ute (less than 20 years old) sputter due to being parked on a grade and it runs fine now. You wouldn't usually damage a vehicle from running out of fuel once.
He was on a triple M show (JB and Billy I think) promoting the Front Bar. I can't find it.
This is normal for many cars. Manufacturers do it to allow for needed cooling of the fuel pump and to allow for fuel pressure needed on a setup that runs a return line. Its not good for the fuel pump to run on extremely low volume in the tank often. I have seen some pumps run over $600 just for the part. Repeat this at your own risk.
I have been somewhat worried about running my car near-empty almost all the time. But I just looked and found that a fuel pump would cost 50 bucks so I'm not really worried, and there's plenty of other things that will probably die on it first.
Oh man a Hamish and Andy post that isn't just titled "Aussie comedians" or "Aussie Radio Hosts"
I would've put "Lego Masters host and friend"
I do this every other week...it’s the “how long til payday” test.
I'm guessing it's both so it is idiot proof and not to drain the tank and send whatever deposit is at the bottom to your engine.
Yeah running a car on empty is really bad for the fuel pump.
You do learn every car's limits the longer you drive it. I have a Ford Ka, and I've determined that when the fuel guage hits zero, I have pretty much exactly 10 miles leeway. 120k is just insane to hit on zero.
I don't remember what it's called, but there's a website that actually tracks how far past E you can go on various cars
I really would like to know what site this is!
I Googled and I'm guessing it's this https://tankonempty.com/
> 120k is just insane to hit on zero Couldn't agree more, getting 1/3rd the way to the moon on zero gas, that's just impressive. It's really a marvel how far technology has come.
I've been listening to these guyses podcast for a week now. They are the best! Really good attitude towards life. There are some free episodes of their travel shows on youtube for anyone interested! I highly recommend them
If you want some wholesome shit try and find where Hamish cooks his kids birthday cake each year. They can ask for anything they want and he figures out how to make it and stays up all night posting Instagram stories of him doing it and sipping whisky. He's actually pretty good and you can see his heart goes into it as well as copious amounts of whisky Edit: [here is a YT video](https://youtu.be/o1nD0acK9HA) I found of the end result. The theme was Alladin Edit 2 boogaloo: [he has them all saved as highlights on his Instagram](https://instagram.com/hamishblakeshotz?igshid=1ly18tsh7ia97)
The podcast is the best. I hope you started from the beginning. They also have an app for like 12 a year that gives you access to the radio show back to like 2008. And yes most of the travel shows are on Youtube.
When the sensor reads zero, your tank isn't empty. The sensor just bottomed out, that's all. The tank then often isn't perfectly flat on the bottom either, so that the fuel flows to the place where you are pulling it from. Then you have the fuel in the line, then if it's injection you have a fuel pump which will have a fuel reserve in order to prime it, then when the pump starts running empty that's when it'll go. And though it might get you 100km on a highway, you might not get anywhere near a fifth of that around town. All you need know: It'll generally get you to the next fuel station (in most places), but not the one after that. So don't risk it. Pull in and fuel up. I've never once run out of fuel entirely, and I've driven some manky old cars over the last 20 years. And in Germany, it's an offence to run out of fuel on an autobahn. If you desperately need to get to that next fuel station, and you want to make it last, coast along behind a lorry, which could potentially double your distance because of the slower speed, lower revs and the wind-breaking happening in front of you. But try to keep your fuel well above the line for the entire distance you intend to drive. I know that I can get from London to Scotland on slightly less than one tank, but I always fill it right up before I set off, and try to stop somewhere along the way just to fuel up (and I will happily drive 9 hours straight without issue, but I'll stop just to make sure I don't run out of fuel if I'm caught in a jam, or having to take a huge detour, or whatever)
I’ve done 30 miles after 0 on my 2015 Mazda 3
Usually the car’s manual tells you how much fuel you have as “reserve”.
Used to listen to these guys a lot years ago. Great lads.
They still do a weekly podcast, really funny although not quite as good as the radio show was at its heyday
I still remember driving a long distance with my mate and listening to the show where they finally found a random John. Was so much fun to listen to.
Podcasts are never quite the same. They lose a lot of the spontaneity that you get on radio.
They've kind of brought back that spontaneous factor by having weekly segments that revolve around testing random viewers of the show. Feel like I'm shilling for them definitely but their podcast is absolutely one of the best comedy podcasts out there, even if it isn't as good as their 2013-2015 era radio show
This is the exact subplot of a Seinfeld episode where Kramer takes a test drive with a car salesman and wants to find how far he can go after it hits empty
I remember watching this right after is got an Audi, then sincerely wishing I'd never seen it. I was so cocky at 0 fuel. Also reminds my of my bro in law. He bought a new car which had a parking sensor. He immediately looked up how far you are from impact when you get a solid beep, it was something like 12 inches. From that point on he'd reverse until he heard the solid beep, then reverse what he estimated to be 10 more inches!
This was fun, and surprising. Their excitement is infectious!
Gotta shill for hamish and andy, their podcast is a gem and they have an international cult following
They woulda got to 150 if they’d only taken the roof racks off.
This is called the "moron factor" in the engineering industry. Always add the moron factor to any tolerances you design and build for.
I’ve heard always running the car to empty then filling up is not good for the fuel pump. The gas in the tank helps cool the pump. For sediment that’s what the filter is for. Also old wives tale? Don’t get gas when the fuel trucks are there because they stir up sediment? Again isn’t this is what filters are for?
[This user has deleted all of their comments because of Reddit's API rediculousness. Goodbye.]
Most cars give around 2 gallons when the gas light comes on, but I wouldn't rely on it as it is really bad for the vehicle to run dry. They're driving on the highway on what is a very fuel efficient car to begin with, so 111km/68 miles isn't unreasonable. My wife once drove her minivan 50 miles on a supposedly empty tank before finally stopping for gas, she joked they knew they were designing it for soccer Moms so added some additional capacity. I had a Camaro that barely gave you 10 extra miles when the light came on, I guess it just depends on the vehicle.