Quick Question

[Country Mav]

I've always run 15W-40 in all of my diesel engines, but I've noticed that a lot of people on here run 5W-40. What's the reason for this? I'm close to the 5,000 mark on my oil change, so I want to put a full synthetic in it- what would be better for our 105+ F heat down here in Louisiana in this 6.0? 5W-40 or 15W-40? Thanks! Preston

[05harley]

here is the debate on oil


Best Oil in a 6.0

[Rick C]

Google SFR products and watch the demo. Truly amazing and I have seen the demo live using my own products. A friend of mine has run the stuff for 15 years. Ran it in his 89 Dodge Cummins 500K + miles. Ran it in his Getrag 5 speed and never had any trans failures, same in the diff...never had to rebuild the diff in that many miles. For oil I run Valvoline synthetic...high temps...no real noticeable issues with the 5w40. I may switch to Mobil1 Turbo 15w40 only because my oil temps tend to run a little high when I tow...IDK.