If anyone out there is an oil furnace tech or knows a good deal about them or whatnot help me out please. I am curious to find out if heating oil is very similar to diesel. I had heard a rumor a while back that it was the same thing really but with a dye so you couldn't run it in a vehicle legally. So is diesel and heating oil the same thing? Also if not then could you use diesel instead of heating oil in an oil furnace? Thanks and apreciation for help!!