Quote:
Originally Posted by BimmerMan33
This is a controversial topic....
You'll get several different answers....
Here's my take,
Winter weather:
5W40. 0W40 if frequent starts in cold weather. Prefer 5W40 if you'll be revving over 6000 rpm in winters (of course once up to operating temp)
Summer/Non winter weather:
5W50. 10W60 preferable if frequent or aggressive track use.
I prefer Redline since it claims to have extra ZDDP which lowers engine wear.
Rod bearing clearances in our engines are considered to be tighter than industry average, that's why you need a thinner oil in cold weather so it flows better on start up but also need thicker oil when revving high since the tighter clearance shears the oil and makes it thinner.
So basically the oil viscosity need changes based on ambient temperature and type of use.
BMW just recommends 10W60 based on the expectation that you'd track the car and a lighter oil for aggressive track use could damage the engine.
I feel most auto manufacturers try to stick to a single oil viscosity recommendation, maybe to avoid confusion for the non enthusiast drivers...
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Thanks, I am running with BE bearings, will think about using redline 5w-40 for just this winter.
my drive style is like a grandma, I usually keep the RPM under 3000 lol.