If you've got access to the WVO then that's the way to go, but there are a lot of guys on here that will give you horror stories about it. So its a good idea to search it and know what your getting into really well. If you do it right, you won't have any problems.
I run wast motor oil, its a little thinner and much eaisier to work with in my opinion. I have a PABiodiesel centrifuge, I prefilter into a 55 gallon drum with a 150 micron filter, then heat the drum to almost 400F to get rid of water, make 4 passes on the centrifuge, then into the truck.
My front fuel tank now has two 5/8 copper tubes running through it with hoses coming from my heater hoses. After about 15 min of driving, my front tank is hot to the touch. Need to insulate it better, and i really want a line heater for this winter, but i when your a cheap "butt" you do what you can
