D.G.

Aside from the cold-in-the-morning issue I've always assumed that 15W-50 is better for the bottom end where oil is forced into the teenie weenie spaces by the oil pump, and 0W-40 is better for the top end where it must flow down the guides, etc., with only gravity to help it along.

Having said that, I've always assumed that I'll need to rebuild the top end at least once during the life of a car no matter what I do, but I can make the bottom end last forever if I use the best oil, change it regularly, and don't abuse the engine.

Therefore, I've always chosen the oil that favors the bottom end and kept a little money in the kitty for when the top end needs to be rebuilt.

Besides, a valve job is a lot cheaper than cracking the case.

Does this logic make sense in a 911?

D.G.