fuel leak at return fitting
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Posting Guru
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From: Florida
fuel leak at return fitting
Looking for some advice here. The driver's side return fitting sprung a leak last week out of nowhere three months after install. This is the strictly diesel regulated return, had an FRX installed previously.
Leak is slow, leaves a small puddle after having been parked for a while.
Took the fitting apart this morning and reinstalled. After multiple checks it really appears to be leaking at the "AN" junction versus the NPT to the head.
However, it seems like the NPT is hitting a hard stop and it looks like something is contacting the nut part.
Here is a pic I took of the location on a motor not in a truck (square bolt):
Here is the general view of the area on my truck:
Here is the screen of a borescope showing a closeup of the connection at the head. Notice the white "stuff" contacting the nut top-left. The threads are not bottomed-out:
As I said, leak really seems to be coming from the AN which did not appear damaged. Would overtightening this connection cause it to leak?
Anyone know what this "white stuff" is that the nut is contacting? It seems to be stopping the fitting but again leak seems to be coming from the top connection.
Any and all advice would be greatly appreciated. Thanks.
Leak is slow, leaves a small puddle after having been parked for a while.
Took the fitting apart this morning and reinstalled. After multiple checks it really appears to be leaking at the "AN" junction versus the NPT to the head.
However, it seems like the NPT is hitting a hard stop and it looks like something is contacting the nut part.
Here is a pic I took of the location on a motor not in a truck (square bolt):
Here is the general view of the area on my truck:
Here is the screen of a borescope showing a closeup of the connection at the head. Notice the white "stuff" contacting the nut top-left. The threads are not bottomed-out:
As I said, leak really seems to be coming from the AN which did not appear damaged. Would overtightening this connection cause it to leak?
Anyone know what this "white stuff" is that the nut is contacting? It seems to be stopping the fitting but again leak seems to be coming from the top connection.
Any and all advice would be greatly appreciated. Thanks.
Cargo Master
Joined: Apr 2007
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From: St. Louis, Mo.
It's hard to see on the boroscope pic, Did somebody use pipe dope on that fitting maybe when installed ? Shoul'nt need it but thats all I can think of. Might try to tighten it just a little & see if it seals up. Just tighten a little at a time till leak stops, hopefully
Freshman User
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These threads need to be 110% clean and dry to make a perfect seal. If there's any crud it WILL mess with your connection.
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Posting Guru
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From: Florida
The white stuff on the threads is teflon tape. That's what I used on the other three connections too. The other white stuff is not in the threads but appears to be maybe some sealant sticking out from the intake manifolds.
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Trim it off!! If that's what's holding the nut back trim it. I'm not sure what white stuff someone would use on a valve cover but it doesn't need to be sticking out like that.
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From: Florida
I'll do that thanks. However, I just checked twice more and it really does seem to be leaking at the other connection which just seems to be really unlikely.
Checking by running the pump while holding a paper towel around just the upper part- towel gets wet.
Checking by running the pump while holding a paper towel around just the upper part- towel gets wet.
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Posting Guru
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From: Florida
I keep being forced inside by intermittent rain deluges, but pulled the intake pipe to get some more room. Trimmed the material, it is very soft grey silicone from the manifold. Definitely not stopping the NPT. Maybe it was just tight.
I'm going to reinstall and try to get the hard line to fitting connection tighter I guess. Inspected again and it looks fine...
I'm going to reinstall and try to get the hard line to fitting connection tighter I guess. Inspected again and it looks fine...
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Posting Guru
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From: Florida
That must've been it Tim. Leak seems to be fixed, third time's a charm. Likely I got a better angle on it with the intake tube out of the way.
Bonus- found intake tube split top and bottom at the turbo connection so JB welded that while it's off.
Bonus- found intake tube split top and bottom at the turbo connection so JB welded that while it's off.
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