Castrol 5W-50 (API SL/CF) for 300SD?
 

Dear friends:

I've rummaged through my garage and found about 8 quarts of Castrol Syntec 5W-50 (API SL/CF) I bought a long time ago. Since most dino oils for diesel are 15W-40, I wonder whether 5W-50 is too thin for diesel (a 300SD)? I believe that Mobil Delvac 1 is 5W-40, so it seems that Castrol Syntec 5W-50 should be OK too. I wished I bought Castrol Syntec 20W-50 before.

What do you think? Anyone has used this oil/weight in their MB diesel?

Thanks.

Eric

P.S. I knew that Castrol Syntec is not true synthetic oil, but I bought it because Castrol USA was having some very good promotion at that time :)

That should be fine, but anything lower than 5W shouldn't be used. The first oil change in the 83 I used some Castrol Syntec Truck 15w40, figured it should clean stuff out before going to a full synthetic. :)

I think it's OK... just don't leave it in there very long. I'd change it by 5000 miles and go back to a quality synthetic like M-1 or Amsoil. Also, it is approved by MB as well:

http://www.whnet.com/4x4/oil.html

:)

Speaking of Catrol, has anyone used Castrol Elixor which is used quite extensively on the truck racing circuit in Germany. Seems to be a high performance diesel oil.

From what I have seen all synthetic oil weights have a "C" rating. It just when it comes to dino oil, only 15W-40 is rated for diesels.