PSA: fuel heater on 12 valve Cummins

Oct 3, 2022
I'd heard in the past that the pre-lift-pump fuel heaters on mechanical 6BTs can cause issues, but I saw it firsthand last week.

Customer said the truck wasn't starting, I found no fuel getting to the injectors when cranking. And no fuel to the water separator. Also, the primer on the lift pump was seized and impossible to push. Took off the lift pump and heater assembly, heater was ancient and probably original. Wires weren't even connected; they were ripped out. I took it apart and it was both partially disintegrated and partially plugged up with junk.

I got a heater delete kit, a new lift pump, new water separator element, and I took off the hard line from the lift pump to the water separator and blew it out with air. After putting it all together and priming the fuel system, truck runs and drives great again.

If you own one of these trucks, might want to check up on that!