The Completely Pointless Thread II

[LKTraz]

0

5W50 is becoming a more common oil weight with today's performance engines. Diesels have been using heavier weights for a while and some of them are also approved for both gas and diesel engines. You need to sook for "S" and "C" ratings. S being gas and C being diesel.

If there are S only ratings (SF....SE....SC etc) they are gas only as just C ratings would be diesel only. For example, Rotella T 15W 40 is rated CE CF CC CD SF SD SC SE. It can be used with a pretty wide range of both gas and diesel engines. Being a bit heavier it works great in higher mileage gas engines and is the recommended oil for most new diesels. I use it in my vehicles because of 1) the heavier weight and 2) I can get it at work for all but free!

I have seen some new high horse engines call for 10w 50 and 1 or 2 using 20W 50 for warm/hot weather conditions.

Pretty much it's due to better oil pumps/return journals in new engines. The heavier oils provide a better film coating at more extreme heat and harder operating conditions.

Just imagine this......top fuel engines are typically running 20W 80 oil!