Do not get caught doing that. It is a federal offense. You are burning fuel w/o the road taxes on it. They check OTR truckers all the time for this and there are BIG fines for running off road diesel, which is red. Diesel is dyed green.
At one time diesel fuel had certain lubricants in it for IPs and injectors that fuel oil did not. Not sure if that is still the case however. Today they run 5% BD for lubricity in almost all diesel fuels. It also stretches petroleum stock further so maybe fuel oil gets it too.
ive been running red diesel in my cars for years, and my dad, hes been running it too, for most of his life. most cops never think to dip the tank of a VW rabbit or jetta.. hell, most cops are oblivious that there is such thing as a VW that runs on diesel..
i had a beer keg in the back of my first rabbit. 15 gallons. and i had quite a few cops check it out. they always assumed that i had a keg of beer in the trunk of my car, none of them EVER noticed that it was red fuel, and not green.
anyone remember when diesel was still golden colored? and had sulfur in it still? i had some high-sulfur diesel not too long back, and i really couldnt notice a difference, other than it smells just like i remember diesel smelling when i was a kid..
i think that if we treat our diesel with some sort of lube that it is every bit as good as the high sulfur stuff..
anyways, ive never had a problem running furnace oil in my diesels. i dump 2 cycle oil in every drop of fuel that goes in my car, so i dont care what kinda fuel it is, its not going to hurt my injectors or pump. might clog my filters, but its fine on the hard parts..
make sure the fuel is clean.. now days, #2 diesel, heating oil, off road, all of it.. it all comes from the same original tank. its just got different additive packages now..
the only difference between #2, and dyed #2, is the dye.. the fuel is exactly the same..