I have been running a blend of about 30% in my '03 and Liberty with no problems. I have been blending up to 50-60% in my '96 and equipment with no problems. I filter twice with a 10 micron water block filter, after letting the oil settle for 2-3 months and draining the "sludge" off the bottom. I have had zero problems. Cuts my fuel use in nearly half in the Summer. I do no refining, just blend the double filtered oil in regular ULSD. I blend less in the Winter because of viscosity of the oil. I bought the stuff to "refine" but decided it would be a hassle for the amount of fuel I use, plus the methanol is highly explosive and expensive. Blending works great for me, smells good, cuts fuel use way down and adds lubricity, plus I get about 60-80 gallons of good clean waste cooking oil a month for free.