how often does everyone change their synthetic oil?????

[Unregistered]

Man, you guys are all over it. If you want a good laugh, go to e46fanatics where every other post is pratically, "why does my need oil light keep coming on?", or "if BMW says change every 15,000 miles it must be best for the engine."

I change according to the service indicators with Mobil 1 0w-40 (A good Group IV synth v. Castrol's Group III crap). Normally, I agree with 7500 miles as a reasonable limit, but for a few reasons feel confortable pushing it out to 8500 or whenever the lights come on. BMW's (and most german cars) have large oil sumps compared to domestic and Japanese cars, which allows for longer intervals. Second, synthetics maintain their additive package longer than mineral oils and are suited for longer change intervals.

As another poster said, check out bobistheoilguy.com There is a wealth of information, including Used Oil Analysis.

Cary

[Dick Schneiders]

That is certainly thick enough for the hottest months. We used to run 10w-30 year round with non-synthetic for many years.

Certainly there is nothing wrong with 15w 50 in the summer, but the 40 weight oil is quite thick enough.

I know on the older m30 motors there is a recomendation for thicker oil in the summer months. I would be somewhat leary about running 0w40 when its 95 degrees out, with the air on and the motor humming along. I run 15w50 April to November then 0w40 for the rest of the year.

[Unregistered]

That is certainly thick enough for the hottest months. We used to run 10w-30 year round with non-synthetic for many years.

Certainly there is nothing wrong with 15w 50 in the summer, but the 40 weight oil is quite thick enough.

I agree. The 0w-40 is approved for all temps and what I would use year around in all climates. There is no problem with using the 15w-50 in the warm months as the poster above said he does, but no benifit either. The only time I would consider 15w-50 necessary is in a track car or street car that is seeing extended high speed operation in 100f+ weather (by high speed I mean 100mph+ for more than 10-20 minutes at a time).

Cary