05 freightliner losing prime? Or..

X2 on the return check valve. I have only changed two, one was cross threaded by a previous shop, and the other one was requested by a customer and it didnt fix anything

 

I have an '05......mine did it too and the problem was injector tube! Got so bad it had to be started with starting fluid and then to the point of not at all!

That check valve is the "hot thing" on truckers report!! Just like the bull gear!! Many and I mean MANY Detroit techs will tell you, rarely does a bull gear fail, same as that check valve

 

I have seen a few check valves fail. They just get weak. You can take it off and blow through it to test the strength. If you can blow through it with your mouth then it is weak. They run about 110.00. But I don't think the check valve is your issue.

 

will differ. bull gears do go out on detroits. checks valves do go bad, the o ring or the spring can fail, mine did. also bull gear bearing, I several neighbors who all had bull gear problems with detroits. there is a big truck shop & truck sales in Birmingham al, Geralds. the owner told me he keeps a shelve full of detroit bull gears cause of the many he has had to replace.

 

I AM glad for this info. today I just replaced my fuel sending unit in one of my tanks & it was black. & there is black coating on the inside of the tanks, but the fuel in the davco is clear as new. I have very tiny air bubbles in my davco at times. I just thought it may be a fuel line not tight, all are new. maybe time for new inj washers & -o- rings. thanks John

 

I am retired now but still get involved when freinds have problems, yesterday I helped a freind who could not get his tractor primed, I have a small air tank, with female air ends in each end, and a 3/8 pipe plug on the side, I fill it 3/4 with fuel then charge with shop air, I have a tee with a ball valve so I can connect the system, one to put in a guage, I used it to find leaks, many times I would block off the return, and suction lines and presurise the system.
That thing works great on units that are run out of fuel, if you ever had a "E" it works on them.
Just a thought!

 

what if fuel has no abnormal look, but the fuel fittings & other items in the tank have a black soot like coating?

 

Detroit 60 14l loses prime, same problem different truck: I read through the posts for a refresher. 1: fuel in Davco. 2: No continues bubbles in fuel tank out of return line. 3: No compucheck fitting on outlet of fuel pump on this truck, would have to remove sensor and plumb into that port. 4: Decided to remove check valve behind head and test with air, seemed OK, filled inlet side with fuel and stood up on hole in step, it was empty in about 15 minutes. Disassembled check valve assy. and found a broken o-ring, replaced and Detroit life is good again. Thank's everyone for your posts and I hope this helps you or someone else in return.