is it safe to go 20K on same oil?

[kickster]

car 1990 Golf 1.8L 8v.
Mileage: 260,000 KM
I already have 4000KM on AMSOIL 5w40 and I was hoping I can drag this oil until next spring but by then I will have over 20,000KM on the oil. I will replace the oil filter at 10000 mark. Do you think it is safe going that long without doing a UOA?

 

[Al]

Not without an oil analysis IMHO

 

[John in the ATL]

kickster,

I believe that Amsoil could go 20k km/12.5k miles if you were using lube control and fuel power to control thickening and insolubles. Used oil analysis preferrably with someone like Terry Dyson consulting you.

 

[Eiron]

Well, Amsoil says this oil can be used where GM-LL-A/B-025 is specified (30k km or 2 yrs in a gasoline engine & 50k km or 2 yrs in a diesel engine). It sounds like your plan of changing the filter at 10k km would make it easy for this oil to go 20k km in your engine.

 

[Ugly3]

Look at the synthetic oil life study - Mobil 1 went 18,000 miles with a filter change at 12,000 miles.

Amsoil has gone 10,000 miles with no filter change and is stil going but not looking too good right now.

Going much beyond 10,000 miles without oil analysis is foolish in my opinion.