Have a 99 Dodge Turbo Cummins Diesel,( 24v) it has about 78,000 miles on her.
Only had it for about a year, bought it in Texas, and brought her Norrth to Illinois, to live in the Land of Lincoln!!! LOL
Anyway, my question is what weight of oil is common to run?
I'm thinking of putting a synthetic in it, but really not sure of the brand or weight to use? 10w-30?, 15w-40?,
I run 10w-30 in my car, but I'm new to diesels and not sure what is right?

Thanks!

 

15w40 is the most common dino oil. 0w40 and 5w40, as well as 15w40 synthetics are getting easy to find as well. When looking for oils, check the back and make sure it is CI (compression ignition) rated, or CF-4 or better (I believe it goes to CJ-4 now), or API diesel emblem, or see if it says something about being approved by Cummins.

 

15W40 is a good all around weight. Pure synthetic oil works just as well with that weight at - temps. If I remember correctly, one brands (not giving specifics) 5W is only good to -5* more than it's 15W.

 

On my 2003, I run either Rotella 5w40 or Mobil 1 5w40 diesel oil for winter and Rotella 15w40 for summer time.

 

Thanks for the input guys!!!
Was leanig towards 15w-40 in a synthetic.
I see alot of you must run the Shell Rotella?
See some posts on Amsoil, and seen someone say something about Valvoline Premium Blue, guess I couldnt go wrong with any of these. Does Castrol have a good synthetic? Always see their commercials.

Thanks Again!

 

I run 0w-40 synthetic year around. Never any problems.