@barncobob posted:Ram diesels love this oil but 15w/40 5w is pretty thin unless ur in Antartica..probably a good choice 5w40..thats the weight what Por people run in their 991s..but alot like Motul 5w40
You're missing the point of multi grade oils, Bob- it's only thin at start up, where even 5w doesn't flow immediately through the tight bearing clearances most engines are built with today. Whether the ambient temp is -10 or 105°, at start up the engine is cold and an oil with a lower 1st number will flow, lubricate surfaces and carry away heat sooner than an oil that acts thicker when cold. The current trend with most car manufacturers is to use the same (low first number) weight oil year-round because they've realized that ambient temp doesn't really have much of an affect on an engine's running/performance parameters.