1996 BMW 328i S6 what oil should I be using?

[CATERHAM]

I can't give any first hand experience with the 4 cyl Bimmers but from what i understand they did require heavier oil to maintain adequate OP at least the earlier ones.

As I mentioned the BMW 5W-30 oil shears a lot so it's virgin HTHSV of 3.5cP is undoubtedly no more than 3.1cP or so in service. Anyway, BMW spec's a 3.5cP oil since oil temp's can get quite high if you track the car. Bimmers are sporting machine after all.

 

[fdcg27]

The e30 or e36 fours have about two liters less sump capacity than do the sixes, and the sump is alloy and nicely finned, so this may be a factor in bulk oil temperatures.
The fours used in these cars do have higher specific output than do the sixes, but in most situations, this isn't a factor, since it doesn't take all that much power to cruise along the interstate at 80 mph or so.
Unless you track the car, you rarely have the opportunity to run it hard enough for long enough to seriously heat the oil.

 

[Garak]

Originally Posted By: CATERHAM
An OP gauge is an effective viscometer. If the oil pressure is "fine" then the operational viscosity in more than adequate.


This is what a lot of people forget. German cars' FSMs often have oil pressure values listed for various RPMs and at idle. So, one certainly has the option to make a viscosity selection based upon that.