going to use Castrol 5w50

[Russell]

Seems llike a great synthetic oil for year round use. Not sure that Mobil 1 0w40 is the best oil with my m50 engine with hydralyic lifters. I think slightly heavier oil would be better. The 0-5 part is better for cold start pump up as it will eliminate/reduce a rattle you get with heavier 20 weight oil on the M50 engine.

Just my experience to date

[liquidtiger720]

I've been using it since ~ December.

someday, I need to get a oil analysis done.



I still get a lot of rattle on cold start ups....but it goes away within a 5-10 seconds.

[Rob]

I'm using Shell oil. 20w50 is this okay? I get the rattel on a cold start up, however it seems to go away after a while.

[Russell]

Mine used to have the same rattle. However, after two engine cleaning/rinse steps with Auto-rx, it seems to have minimized this winter even with 10w40 conventional oil. Hope it does not start again with the 5w50.

[Rob]

Isn't 5w way too low?

[Russell]

Depends on climate. In a very hot climate 5 weight may be to low. However, her in my area in the US it very seldom gets over 90 F and in winter very seldom gets down to 0 F. Also it is my understanding (not sure) that synthetics allow a wider viscosity range. Also the lower number refers to viscosity at a cold start up, when warmed up the oil is a 50 weight.

Not sure this is a good answer. You may want to search one of the oil fourms such as bobistheoilguy. also keep in mind that one of the more popular oils for our cars in the US is Mobil 1 0w40 oil.

[Paul in NZ]

synthetics oils cannot be judged by dino standards,eg 5w30 sythetic allows faster pumping at cold start up AND superior protection ay higher temps even with lower "higher" viscosity numbers

[Rob]

Well here in South Africa it can get very hot. On most days we see temps of around 27c to 31c. The oil I put in my car along with a new oil filter was Helex Super 20W 50. Does that sound okay to you guys?

I did notice a big difference with a new oil change. She felt lighter on the accelerator and easier though the gears. But she does sound a little rattey on idle when I first start her up. Should I be worried?

[ryan roopnarine]

did you try the german castrol 0w30 in it after the mobil 1? 10f-90f sounds like it would be just up that oil's alley.

[Russell]

No, I did not try the GC 0w30 for two reasons. The real green German Castrol is very hard to find. As far as I know, it is sold only hit or miss by Auto-Zone and I am a bit leary of a 30 weight oil in an older BMW engine. Still a strong consideration. Thanks