Repeat return line O-ring failure

[reklund]

Hey guys-

I've had repeated return line O-ring failure on the same cylinder. About 6 weeks ago, I began smelling Diesel when I approached my truck after it'd been parked. As the smell persisted, I traced it to leaking return line O-rings on the #5 cylinder.

I replaced only the O-rings (while I awaited an entire return line/cap kit to arrive) and the problem was solved. There was no obvious signs of a failed cap, and the old O-ring did show signs of being pinched (which is weird- it was on there for over 2 years with NO issues). Today, same leak, same cylinder. I haven't pulled it apart yet, but am curious what may be causing it. The truck runs/starts/drives normally, but leaks diesel.

Possible bad injector sticking open causing combustion pressure to be forced into the return cap? Can that even happen? Is my truck telling me it needs a Moose Pump and Moose Misters?

Ryan

 

[icanfixall]

If the injector is hanging open it will be hot to the touch... Hotter than the other injectors. Next time this happens remove the injector and look it over closely. The gasket will need to be replaced but... If you don't have a new gasket heat up the old one and quench it in cold watwe. That will anneal (soften) it. Then file it flat on a smooth file to get out any pits.

 

[franklin2]

It's going to be difficult to overwhelm the return system, since when I had a line crack I routed one fuel line from the pump directly into the return system and it didn't leak. Have you tried wiggling the cap back and forth a little bit? That may re-seat the o-rings and stop it.

 

[hesutton]

Like stated above, an injector sticking open can ruin the o-rings/cap pretty quick. The cap can get deform or even develop a hole in it when this happens.

The truck would really like the Moose fuel system.

Heath

 

[reklund]

I'll replace just the O-rings again at work tomorrow, and see what is causing the leak to return.

I'm thinking this might be enough to push me over the edge into Moose-dom! Lets see... Moose Pump, 8 Moose Misters, 8 new ZD-9's, a new return line kit, some fiddling with the wastegate.... Yup. I'll go faster or blow it up trying!

Ryan

 

[Ironman03R]

I fought with mine for a couple years changing o-rings as they started leaking evry couple months. Before the rally I replaced all the o-rings with Viton o-rings and used goodyear fuel injection hose for the return lines. So far no leaks.

 

[reklund]

Got it fixed today. All the passenger side return caps had hairline cracks, and the #5 was actually cracked on the inside causing the leak.

I still have the drivers side to do, but for now the leak is buttoned up. If I hit my bonus the next few months, I'm going to consider moose-ing my truck anyway. It's time for another mod!

Ryan

 

[LIGOOMBA]

I fought with mine for a couple years changing o-rings as they started leaking evry couple months. Before the rally I replaced all the o-rings with Viton o-rings and used goodyear fuel injection hose for the return lines. So far no leaks.

Hi im new here with the same type of proble.I replaced my caps,o rings,lines(used the line with the braid covering)The truck ran fine till one day it would not start up real quick.I noticed some fuel near the rear manifold,Any direction to go in.New to the 7.3.
P.S. where can I buy the Viton O Rings and the fuel line with the braid over it or some Goodyear line.
Thank You

 

[icanfixall]

Typ4 sells the return line kits here and they are cheaper than anyplace else. He also has the viton o-rings...

 

[Agnem]

Welcome to the site. Check our tech articles section, and look for the parts bin. I believe there is some Viton O-ring info in there along with hose info.