Well...dyed diesel could be ANY kind of diesel....dyed diesel is not a type of diesel...the dye is a marker to keep diesel that tax has not been paid on out of road vehicles. The reason I brought up the ULSD is: it's being stated by some that because of the lack of lubricity in it....it's causing engines to wear faster, thus causing shorter rebuild times and oil burn. Although 3500 hours does not sound like a lot, it's the same as having almost 200,000 miles on a road tractor.... and there seem to be a lot of road tractors getting rebuilds in the 200K to 300K mile range all of a sudden.....