Ghunt I have never run wmo or even tried it but dodge cummins does and has had no ill effects. What I have used is oil out of transformers I had a friend that used to buy them from the electric companies and gave me about 5oo gallons of the oil. I was afraid to run it 100% because I think it was highers but mixed it approximately 50% and I say approximately because I just pumped it in until my guage read 1/2 tank then filled with diesel all winter with any bad effects filters or pump problems, and used this pickup daily for a couple years after this supply ran out.