Overheard a guy at the parts counter say injectors don't fail, they just get neglected

I was picking up a fan belt for a 5.9 Cummins last Friday at the shop in Akron and this older mechanic is telling the kid behind the counter that he never sees injectors actually wear out from age or mileage. He said it's always dirty fuel or water in the system that kills them. That really stuck with me because I've replaced three sets in the last two years on fleet trucks and now I'm wondering if I should be checking the fuel filters more often. Our shop does them every 15k but maybe that's not enough. Anyone else ever hear something like that or am I just overthinking this?

3 comments

3 Comments

josepha321mo ago

lol I mean dirty fuel can definitely kill injectors but three sets in two years sounds like you got bigger problems than just filters lol. 15k intervals are pretty standard for most fleets I've seen and unless you're running some real junk fuel I'd be looking at how the trucks are actually being driven instead. Seems like one of those things where mechanics like to simplify stuff down to one cause but reality is usually more random than that.

michael_jenkins391mo ago

The fuel tank tip is solid. I'd start draining the water separator every week on a few trucks to see what comes out. Also if you are running any kind of aux tanks or getting fuel from a bulk supplier I'd test that source first before changing your whole filter schedule.

barbarah191mo ago

Man that's a good point from @josepha32. I mean, three sets in two years across a whole fleet does sound high even for dirty fuel. But what about the fuel tank itself - are you guys checking for water settling at the bottom or any algae growth in the tanks? That older mechanic might be onto something about neglect, maybe not just filters but the whole fuel system maintenance routine.