Fuels rails will not stop leaking, ANY advice is helpful!

Stopsign32v

Member
May 18, 2008
394
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16
Gville, SC
Well this is the last thing I need done before I start up the motor. The rails are UPR rails. The rails are leaking where the fittings go into the rails themselves. Its leaking at the front (feed) and at the two backs (cross overs). I've tried ARP thread sealant but it never hardened it just stayed wet and the fuel washed it away. Then I tried teflon tape and after putting a **** ton of tape on the threads I got 2 out of 3 to not leak. I decided I would just weld the damn things to the rails but a fab shop told me not to. Then my friend told me to use this thread sealant he used and it hardened up for him. We put it on and 3 days later it still is as wet as it was the day we put it on.

So at this point I'm either thinking about putting a **** ton of silicone or rtv around the fittings and onto the rails to where it will trap the fuel in the rails after it cures or using JB weld and doing that. I need something that will harden and trap the fuel in the rails. ANY advice???? I'm pulling my hair out here...
 
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They are the 3/8" NPT thread correct? they make a few different styles I would call UPR if the rails are new and get a replacement set. It kinda sounds like you have a rail that is looking for a O-ring. The ARP sealant is non-hardening, along with some of the other liquid teflons, Permatex will get hard.

As far as welding on the male fittings that shouldn't be an issue, not sure why they recommended not doing that. However I use the liquid teflon or o-ring/An style fittings on all the rails I do with no issues.
 
Permatex will get hard.

As far as welding on the male fittings that shouldn't be an issue, not sure why they recommended not doing that. However I use the liquid teflon or o-ring/An style fittings on all the rails I do with no issues.

Permatex is the last thing I used and its as wet today as it was the day I put it on

He said it would get so hot that it could warp the metal. :shrug: I know nothing about welding...I've done it once about 12 years ago. I would think the O-ring AN style fitting would work but I can't thread the fittings in all the way. You can still see threads when they are tight.
 
I bought a Professional Products fuel rail and had the same issues you are having. The threaded holes aren't meant to get O rings and I tried teflon tape, teflon liquid, permatex, furnace pipe thread sealant, you name it. I guess I got lucky because I got all the leaks stopped using one/or some of the above mentioned sealers. I just don't trust it... I'm always checking them after each drive and I'm afraid it's going to spring a leak while I'm driving and I end up dealing with a fire! I trust every part of my car but the fuel rail. I've even thought of putting the stock rail back on because I'm only running 24# injectors so it should do fine... it just looks like crap. I don't want to be worrying about a fuel leak the whole time I'm driving though.
 
Is there actually fuel in the rails at the moment? If there is you've got to get that out of there or nothing is ever going to dry properly. The rails sound like junk personally. I'd try and get some new ones from UPR or go with a better brand. I know new rails aren't cheap, but it's worth the cost of rails to not have a fire and burn up your car.
 
I talked to UPR and they said the usual "We've never had this problem". I told him I didn't give a damn and that I WAS having this problem. He put me on hold and came back and told me to use black high temp silicone on the threads and all around the fitting where it goes into the rails. We will see if that fixes it tomorrow...