I was at a job site last week (I am a service technician for a large oil company who has a big subsidiary company that provides bulk fuel tanks to customers. I fix those tanks when customers inevitably break the pump systems. Anyways, I’m at this job site fixing up a hydro locked engine. Easy fix. During this, the foreman’s son, who is on an excavator next to me wanders off too far and his equipment dies (could’ve just waited for me to finish fixing the engine and he’d have fuel). Anyways, he flags me down to see if I have any on my truck; I do. It’s highway diesel though. And here’s where the train stops.

He asks me “will it hurt my equipment?”

I tell him no. It’ll run fine. And he goes off about how his equipment runs on dyed/ off-road only… no shit Sherlock.

Anyways, I explain that the fuels are identical and that off road is literally just dyed at our fuel plant up the road.

But after having this interaction and physically seeing the dying process and having a period where our dye ran out… I have to ask, is there something somewhere or in the past where dyed off road was legit different in its refining process and how it interacted with an engine? Because we supply over 1 million gallons of diesel a month and it goes out either dyed or clear. There is no other refining process at this point. I’ve ran both off road and highway in both off road equipment and road legal equipment for years with no issue outside the obvious tax issues that come with that. Or the rare occasion of water contamination or particulates like sand or concrete (concrete plant customers). But all that aside, off road and highway are identical minus the red dye. Right?