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Where's the leak?

Hello all! I'm a newbie to Powerstrokes and I was hoping someone would be kind enough to share their experience with me. I have an '04 (mfd. 8/03) 6.0L in my shop that stalls and won't restart when warm, which I understand is pretty typical. At any rate, I've performed the HPOP air test and I'm getting air leaks off both banks. My question is, is there any way to pinpoint the leaks? I can see no smoke, bubbles or trails, and running my hand over the rails and rockers produces no difference in sound pitch. I would sure like to see something conclusive before I tear into it, hoping to find some kind of evidence along the way. Thanks in advance for your input.
 

blacksnapon

Moderator
Staff member
Theres actually tools made to isolate each side. You can Isolate then do an air test, or isolate one side then see if it will start. Theres another tool to just "deadhead" the hpop.
 
OK, so I ended up replacing ALL the o-rings in the top half of the HPOP system (injectors and nipples). Before putting it all back together I made some plugs to block off the braided hi-pressure lines at the log rail connection and installed an IPR test plug. When I charge the lower half with air I am getting gurgling from the oil reservoir/oil filter area. I can hear no air leaks at 100 psi, but it won't hold the pressure and "glug-glugs" down to zero. Does this mean the HPOP is bad? It is allegedly a reman pump with less than ten miles on it. Thanx!
 

blacksnapon

Moderator
Staff member
OK, so I ended up replacing ALL the o-rings in the top half of the HPOP system (injectors and nipples). Before putting it all back together I made some plugs to block off the braided hi-pressure lines at the log rail connection and installed an IPR test plug. When I charge the lower half with air I am getting gurgling from the oil reservoir/oil filter area. I can hear no air leaks at 100 psi, but it won't hold the pressure and "glug-glugs" down to zero. Does this mean the HPOP is bad? It is allegedly a reman pump with less than ten miles on it. Thanx!
Yep, if its coming out of the oil filter housing, its the pump. There's no other way to get air to there unless its bleeding past the pump.
 
Well no, oil isn't coming out of the filter housing, the gurgling is just loudest inside the filter housing. Oil isn't coming out anywhere that I can tell. The filter can is on the engine with the filter removed at this point. I have the HPOP that was removed by the last shop to work on it, and I cannot get any air flow backwards through the pump. That is, blowing in the discharge side allows no air to come out the bottom. But I do get air flow by putting my blow gun on the bottom port, it comes out the discharge hole, as it should, albeit to a lesser degree. To my mind, the gurgling is proof that pressure is back feeding into the reservoir. Am I wrong? Is there something else I haven't considered? Thanx!
 

blacksnapon

Moderator
Staff member
Well no, oil isn't coming out of the filter housing, the gurgling is just loudest inside the filter housing. Oil isn't coming out anywhere that I can tell. The filter can is on the engine with the filter removed at this point. I have the HPOP that was removed by the last shop to work on it, and I cannot get any air flow backwards through the pump. That is, blowing in the discharge side allows no air to come out the bottom. But I do get air flow by putting my blow gun on the bottom port, it comes out the discharge hole, as it should, albeit to a lesser degree. To my mind, the gurgling is proof that pressure is back feeding into the reservoir. Am I wrong? Is there something else I haven't considered? Thanx!
Its the pump. The gurgling is the air inside the filter housing. Thats the only way air can get inside the filter housing, its bleeding past the pump.
 
I don't see how it could be anything else either, Blacksnapon. I just needed to be certain before I tell the owner that the HPOP he just paid a lot of money for is NFG. Hopefully, I can get it warranted for him. It came from a vendor called Diesel Care and Performance Inc. Remans just suck...period. They have had a high incidence of failure for the whole 45 years I've been wrenching, and probably before that, I would guess. Thanx for the consult!
 
Update: After a 3 wk. wait I finally got that Reman HPOP warranted. In fact, they sent two. So I put one of 'em in the hole and put some shop air pressure to it. Gone is the gurgling sound I was getting from the area of the HPO reservoir at 40 psi. In it's place, I am now getting a musical note from somewhere way down deep in the engine at around 90 psi. It sounds like a high-pitched hum or vibration in the key of G# in the fifth octave (I was able to replicate the note on my keyboard). Has any body experienced this phenomenon? Thanx!
 

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