Even though it makes no sense but a real automotive "vegan" can modify diesel fuel heater to
run on regular oil. New or used. Sunflower or whatever oil. That oil will solidify at cold temperatures
but only a small portion should be warmed up with 12V heating element to make it totally usable
in winter. Byproduct is usually a smell of fast-food restaurant exhaust
Particulates that come out of fuel heater exhaust are much safer/cleaner than those that come out of
older diesel vehicle due to no compression of the fuel. Plus of course amount is like 10x less than car.