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      07-20-2026, 11:27 AM   #285
DrFerry
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Drives: 2008 E92 M3
Join Date: Jul 2010
Location: Greenville, SC

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Quote:
Originally Posted by amg6975 View Post
The S65 loves 5W50. In a desperate attempt to lower oil temps I swapped to a 5W50 and it's like a miracle drug for the engine. Temps are lower, it's quiet, smooth, etc...

I don't have any data on long term effects so proceed at your own risk but I've run Castrol 5W50 when I had cats, did oil analysis, everything came back perfect. Since ditching the kitties I've been running Motul 300V 5W50 and from everything I can tell the car absolutely loves it.

I have about 8k miles over three years on the engine since switching, of which probably 7k are hard track miles. Everything appears to be good, oil analysis (which I don't really trust) are good.
Good info, but how about oil consumption? My own experience with Mobil 1 5W50 was that when hot the oil sheared down and got thin enough to increase oil consumption (creep past the rings) using up to about 1qt every 1500miles! But that's Mobil 1 5W50 FS. Castrol 5W50 maybe different. Please let us know your experience with oil consumption using the Castrol 5W50. BE Bearings recommends 10W60 after using their increased clearance bearing shells.
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