Diesel Place banner

Schaefer Oil - 7000 or 9000

11K views 10 replies 8 participants last post by  adamrc  
#1 · (Edited)
I have searched and searched the archive files and could not find a clear answer about 5w 40 verses 15w 40. I live in Las Vegas and there are a couple of dealers here that sell the Schaefers oil and they keep pushing the 9000, however the owners manual says to use 15w 40 above 30 degrees. It is never cold here and most of the time it is 70 degrees or above. I will get to the question now is 5w 40 ok to use in high temperatures or should I stick to the 15w 40 as the manual says. Second question I have been told and read that you should not use synthetic in a deisel motor until 20,000 miles or more, is this true?

Thanks
 
#3 ·
5W pumps better in cold weather. 5W-40 and 15W-40 are at the same viscosity at operating temp.

Go with a 5W-40.
 
#5 ·
No one has answered the second question. Break in of a diesel motor being different than a gas motor what is the correct milage number to switch to synthetic?

Thanks
 
#6 ·
I changed over to synthetic at 1000 miles.... Opinions vary but I see no down side to switching to synthetic early on in it's life.