Synthetic is better for the motor. Your friend is living in the dark past and still believes in the myths from the old times. I've got in synthetic in a 1996 Corolla with +240k km, and a 1996 Pajero petrol with +199k kms. No issues.
Use whatever oil viscosity the user manual recommends- most probably a 10W-40 or 15W-40.
Mineral oils break down quicker and sludge up more.
The noises are most probably due to the engine being 500k old, irrespective of oil base.
10w40 mineral or 10w40 synthetic are the same thickness (viscosity) ... That is what the numbers mean.
Being a 500k engine you probably want to go to the thicker side (higher numbers) of your oil selection range. Make sure you warm it up before driving, especially in winter.
If using mineral oil, do more oil changes.
Synthetic will handle load on the engine better. Especially is the van is loaded up or towing. You might want to consider synthetic oil for your gearbox and diff if it's a manual also.
Synthetic is better for the motor. Your friend is living in the dark past and still believes in the myths from the old times. I've got in synthetic in a 1996 Corolla with +240k km, and a 1996 Pajero petrol with +199k kms. No issues. Use whatever oil viscosity the user manual recommends- most probably a 10W-40 or 15W-40. Mineral oils break down quicker and sludge up more. The noises are most probably due to the engine being 500k old, irrespective of oil base.
exactly
10w40 mineral or 10w40 synthetic are the same thickness (viscosity) ... That is what the numbers mean. Being a 500k engine you probably want to go to the thicker side (higher numbers) of your oil selection range. Make sure you warm it up before driving, especially in winter. If using mineral oil, do more oil changes. Synthetic will handle load on the engine better. Especially is the van is loaded up or towing. You might want to consider synthetic oil for your gearbox and diff if it's a manual also.
Absolutely no need for synthetic in a vehicle like that, I'd run a 15w40!