I bought and have been using some Castrol 15-40 oil. I think it is in their CTX line of oils. It is supposedly designed for diesels and other gas powered RV and heavy pickups with an emphasis on towing protection. Anyone have any other info about this oil?
Tony

 

I haven't seen a new 15W-40 from Castrol. Where did you see it? They have been making a heavy duty 15W-40 called RX Super for many years. PepBoys sells it. I would highly recommend it for older, out-of-warranty trucks. The Diesel rating gives it a more robust additive package.

Jim

 

Yep Jim,
Your correct, it's the RX 15-40. I found it in a Auto parts store. I have an older truck but with a rebuilt motor and am considering either synthetic or this RX 15-40.
Tony