Had a customer swear by ATF in their diesel tank for cleaning injectors

I mean, I always thought putting automatic transmission fluid in a diesel was just an old wives tale from the farm days. But a guy came in last Thursday with a 2005 Ford Powerstroke that had nasty injector knock and swore by dumping a quart of Dexron III in the tank before every oil change. I looked it up on a diesel tech forum and found a study from 2018 that showed it actually helps dissolve carbon deposits better than some commercial additives. Still feels wrong to me though. Has anyone else tried this and seen real results without hurting the fuel system?

2 comments

2 Comments

kellymurphy3h ago

Eh, sounds like a good way to clog a fuel filter.

eric_price1h ago

Not sure I agree with you there, @kellymurphy. I've been running diesel additives for years in my old Ford and never had a single fuel filter issue. Only thing that's ever clogged mine was water in the fuel from a bad station. People get scared off easy by these things but a quality additive used right is pretty harmless. Just follow the directions and you'll be fine.