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leaking fuel rail cap fix

83864 Views 67 Replies 22 Participants Last post by  atoman
First time posting,
I have a 2001 Chrysler Town Country with 3.8

For several months now, I've detected a strong smell of gas under the hood. After watching it for a couple of days, I noticed gas dripping out of the cap on the fuel rail. I found a post where someone removed the cap and replaced the internal o-ring with an o-ring from the fuel injectors. (Same size) I did the fix, and it has not leaked since I replaced the o-ring. The best part was I did not have to remove the fuel rail. (A new one is pricey) You will need to go to the auto store and ask for fuel injector o-rings for the van. Mine came in a package of 2 for 2.39 from NAPA.

Thse are the steps I took:

1) Relieve gas pressure from fuel injection rail:
Remove the fuel pump relay and start the van, running it until it dies. (The relay is in the fuse box)

2) disconnect the battery (just being cautious)

3) Move power steering reservoir:
Loosen the bolts for the reservoir , lift it slightly and push it to the side.
(There are 2 accessible bolts on the top, and one nut underneath that you just have to loosen)

4) Remove cap:
Gently pry the cap off, use the bracket for the power steering for leverage.

The pic with the blue o-ring is the original. (notice the erosion on it)

5) Prepare cap:
Remove old o-ring
Bend the tangs back on the cap so it will fit tightly when you re-install it.
Lubricate the o-ring with some fresh oil and put it on the cap.

6) Install cap:
Put cap over the hole making sure it is centered.
Gently tap on the end until it slides back in the hole and is seated properly.

7) Check for leaks:
Re-connect the battery.
Put back the fuel pump relay and start van.
Check for leaks.

8) Put everything back together:
Move power steering reservoir back and tighten bolts.

That's it, it is pretty simple to do as long as you are careful.
Not once did the CEL come on.
This cap is not for a test port, it looks more like a pressure relief port.

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It is leaking from the "pulse damper" like it was before. It held tight for almost 2 months but then I smelled gas again and sure enough it's the same thing. It's worsening at a much faster pace than before. I've ordered a new rail assembly and will have it Monday or Tuesday.

I do drive my van a lot - over 100 miles a day for work so from a mileage standpoint it lasted a while. But it definitely isn't a real fix for me anyway. I was careful when bending the prongs back into place and making sure the cap gripped the pipe securely. Maybe it isn't a serviceable part or maybe the o-ring I used was slightly too small or something. It's hard to diagnose it exactly. YMMV.
I'd be tempted to try an oversized O-ring if I could find one. I wonder if the cap (hat-shaped thing) or the fuel rail is the culprit, perhaps due to a bit of corrosion? My fuel rail was not pristine and showed some areas of mild surface corrosion.
Take a look at my pics in the beginning of the thread. You have no room for an oversize o-ring.
I thing that would help is to to use a brush to clean the cap and carefully wipe where it seats on the fuel rail.
Mine has not leaked since I replaced the o-ring.
Once you put it back together, it helps to give it a little tug and make sure it not loose.
I was pretty careful when I re-assembled mine. I bent the tangs just so and it held tight after I put if back on. I couldn't remove it without tools. I don't know why some leak again and some don't. Maybe mine has another problem like a hairline crack or something.

In any event I think it's worth trying to replace the o-ring because it is relatively easy, cheap and fast. It seems to work for some people but not all.

Yeah what ever that cap is , I had the same problem and also found that fix it was super easy and at least a year has gone by and still no leak
Thanks Guys. My 2002 Grand Caravan 3.3L V6 has been smelling like gas for months now. We have a trip planned for Seaworld in a week so i figured i better fix this. Quick look with a flashlight while the van was running and i found quite a bit of gas leaking under the power steering reservoir. took it off and found this cap your talking about and gas leaking from it. Followed your steps and and replaced it with a doorman vitroline o-ring. seems good as new. I'll repost if i have any issues after Seaworld.
It has been quite a while since I did mine, and it is still holding up. If I remember correctly, the o-ring is the same as the one for the fuel injectors. I am glad it helped.
Well I finally did mine today. For months I've had a gas smell that came and went, and was occasionally strong. I had cleaned my fuel injectors and replaced all the O-rings a while back, but didn't do the cap (same O-ring). Of course that's where the leak was, so today I went back in.

I took the opportunity to also replace my power steering reservoir. I've been hearing some funky noises and we'll see if that helps.

My procedure:
• To improve access, I removed the two spark plug wires nearest the reservoir from the distributor cap, and two vacuum fittings from the intake manifold.
• Remove the two easy-to-see 8mm bolts holding the power steering reservoir.
• With a good light, get eyes on the nut below the reservoir that must be loosened slightly (NOT removed).
• Coming from behind with ~5" of extension, get a 10mm socket onto the nut and loosen it.
• Pop the reservoir up and out of the way enough that you can access the fuel rail cap.
• I did not disconnect the battery or drain the fuel system. Perhaps because of my leak, there was no residual pressure.
• It was difficult to pry the cap off. I used a couple of wide flat screwdrivers and as someone mentioned, I used the power steering reservoir mounting bracket for a leverage point. I knew I didn't want to risk permanent damage to the cap's integral spring clips.
• Swapped the O-ring and reinstalled, only to observe a serious leak, maybe 3 drops per second!
• Popped the cap off again and fiddled with the spring clips for a while, trying to find the happy middle where the cap is held tightly but will slip on with moderate pressure. If you bend them too far in, you cannot press the cap back on.
• Finally reinstalled the cap. I was not happy with the way it wobbled and did not seem like a snug fit, so I took a heavy cable tie and wrapped it under the fuel rail and over the cap, and tightened it down.
• So far no leak at all is visible. I'm not sure the cable tie is necessary, or how long it will hold, but time will tell.

Here are the additional steps to complete my power steering reservoir replacement:
• Use pliers to move the two hose clamps, one on the smaller return line and one on the larger supply line.
• It took some effort to loosen both hoses by twisting, without risking damage to them.
• With an empty plastic milk jug handy, pull off the hoses and catch what runs out of the filter and the reservoir. With attention to orientation of the reservoir, little should run out.
• Put the new reservoir in place and attach the large hose and return its clamp to the proper position. At this point you can also tighten the 10mm nut and replace the two 8mm bolts up top that hold the reservoir in place. Replace the spark plug wires onto the distributor.
• Plug the small fitting on the reservoir. I used a small piece of hose with the opposite end held up to the top of the reservoir. This does not need to withstand any pressure, just to prevent the fluid from running out.
• Route the small return hose into the milk jug. A high flow will hit this, so be sure it's secure.
• Add fresh fluid to the reservoir, right up to the top. Turn on the engine and rock the steering back and forth a little. It will only take seconds for the old fluid to be pumped out and chased by the new fluid. You'll feel and hear the loss of power steering as the new fluid is drawn in, emptying the reservoir, and pumped back out into the milk jug.
• Remove the plug from the small fitting and attach the return hose and place its clamp.
• Refill the reservoir and top it off as needed after running the engine and exercising the steering.
• I had bought 2 qts of fluid for the power steering, and most of the 2nd quart is leftover. I could have used more for flushing, but I really don't think it would have done much more. I could not have done the job with just one quart, so you really need to buy two.
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You certainly have to be carefully getting the cap off. There is a part number for it, but they are not available anywhere.
It is not even listed as a separate part.
They want you to buy the whole fuel rail.
Glad it worked out for you. As far I know, and I will have to check, my power steering reservoir has never been changed.
the van is over 160,000 miles now
In my case it was the dampener itself that was leaking. Replaced the o-ring just to make sure, the leak was still there -- leaking from beneath the rim of the "hat".

Ended up replacing the rail :(
Bummer. Did it start leaking on its own or did that start after removing it? I wondered as I was working on mine if that seam was leaking, or if I might be damaging it, but I guess it wasn't. No leak now, and fingers crossed.
Well my cable tie "solution" to hold my cap on failed within 24 hrs. I believe it may have loosened or shifted slightly after heating. The tie was still in place but I think the little hat - the fuel rail cap - was cocked slightly. In any event it was leaking terribly. Not so much drops as a steady stream! :angry:

Since my last resort is to buy a new fuel rail, I decided to pull out the JB Weld. Nothing to lose. I removed the cap and washed both it and the top fitting of the fuel rail with acetone to dry up any gas or oil. I applied a liberal bead of JBWeld to the outer brim of the hat, all the way into the center, being careful to NOT get any on the gas-wetted area or the O-ring. I smothered the area around the spring clips. On the fuel rail, I placed a thin layer of epoxy on the upper lip face, and tried to coat the pipe and lip's underside as best I could. Finally, I placed the cap in place being careful to not smear epoxy into the gas-wetted area. I replaced my cable tie to help hold all in place with mild pressure on the o-ring while the epoxy hardened overnight. Things looked pretty good, although I was concerned by the sagging of epoxy. It's thick but it flows until it hardens. I was getting nervous that too much would drain away by gravity. There's now a continuous coating of it all the way down the pipe and onto the fuel rail itself.

So far so good. I just did this yesterday, and no gas is leaking today. We'll see how it goes.

I'm tempted to build a sort of cone-shaped mold under the cap, which I can then fill with epoxy without fear of it flowing down.
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Wanted to chime in and ask if any of you guys replaced the fuel-line coupler/jumper O-ring that is housed in the tee connection? My metal rail cap isn't leaking on my 01GC with 147k, but I was smelling gas in the engine compartment. After I cleaned the area including the coupler seals to the rail, I was leaking from the black cap on the flexline coupler. When I took off the cap (followed SOP for pressure), my O-ring was shredded and worn out. Seems like another Oring to keep an eye on if anyone ever turns that cap. I want to know what size you use since it is not a "serviceable" item and mine is trashed. I made a temp one today with another fluoroelastomer. Viton should be fine especially since lower temp than the fuel injector O-rings, right?

I am hoping that this explain why my van starts a little rough in the morning now (given that the pressure may be lower than normal with the slow leak).

Thanks, Mike
My JB Weld "solution" held for 5 months but failed with the coming of cold weather, which may be just a coincidence. The raw gas smell is back and I can see wetness under that stupid cap. I may try more epoxy as I mentioned earlier. If I build a mold around the cap, I can fill the whole mold, cap and all, with epoxy. This wouldn't be too hard to do but it may eventually fail also. Replacing the fuel rail is more expensive and more work, but I'm getting sick of fighting with this, so it may be worth it to just just bite the bullet and replace the rail.
My JB Weld "solution" held for 5 months but failed with the coming of cold weather, which may be just a coincidence. The raw gas smell is back and I can see wetness under that stupid cap. I may try more epoxy as I mentioned earlier. If I build a mold around the cap, I can fill the whole mold, cap and all, with epoxy. This wouldn't be too hard to do but it may eventually fail also. Replacing the fuel rail is more expensive and more work, but I'm getting sick of fighting with this, so it may be worth it to just just bite the bullet and replace the rail.
You might want to try using the epoxy that comes in one of the many "Fuel Tank Repair Kits" that are available at auto parts stores. The epoxy is designed specifically for use with gasoline, and should hold up better. I would recommend a kit designed for metal tanks rather than plastic tanks.

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Any idea if there is a redesigned fuel rail available, and if so, what its part number is? I can get the exact replacement to mine (as far as I can tell) delivered home for $75, but it's got that same stupid hat on it. That would probably be OK and outlast the rest of the engine anyway, but I'd rather get the "improved" fuel rail if there is such a thing.
There is no "improved" fuel rail, just stick with what came with the van.
If I remember correctly, the later 4th gen fuel rails were re-designed, but will not work with the earlier models.
My "fix" is still holding up :)
It's not a stupid hat,it's a fuel pressure damper,it has a function,and it is needed to dampen fuel pulses created by the injectors.
It's not a stupid hat,it's a fuel pressure damper,it has a function,and it is needed to dampen fuel pulses created by the injectors.
Must have been using special injectors on early 4th gen or the pulses loosen up dirt inside the in-line fuel filter..:confused:

How thick are the tube walls at the damper? can you tap the opening and put a bolt or cap nut in/on there? (with some thread sealer or epoxy)
The true ******* way of fixing it would be to put a hose clamp around the rail over the cap :)
fuel rail cap

I did the O-ring replacement on my 2001 grand caravan and it worked great for about 6 months, so I decided to try it again as its an easy job and it worked for a day. Finally I just bought a new rail and its a job to put in, but so far so good , it has been 3 months. So what I found out is that the tabs on the cap have to bent back to almost exactly where they were, I took off the old fuel rail and noticed that 1 tab under that cap was not under the clipping area and caused it to leak. Its hard to see when its on the van but make sure you turn the cap and that all the tabs are in place. I am glad I changed the whole rail because I know it will not leak again it its lifetime !!
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