leaking fuel rail cap fix

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Thread: leaking fuel rail cap fix

  1. #1
    Join Date
    May 2012

    1 out of 1 members found this post helpful.

    leaking fuel rail cap fix

    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.

  2. The Following 6 Users Say Thank You to blknblu For This Useful Post:

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  4. #2
    Join Date
    Dec 2009
    Thanked 22 Times in 19 Posts

    It's the fuel pressure regulator. Good tip on just changing the o-ring, a new regulator is about $100

    2011 Grand Caravan, 3.6, 141k miles
    1993 Chrysler Concorde, 3.3 145k miles
    1999 GMC Suburban k1500, 5.7, 175k miles
    2006 Pt Cruiser 2.4, 128k
    1987 Monte Carlo SS Aerocoupe 5.0, 76k
    1997 Firebird Convertible, 3.8, 53k
    1960 Corvair Sedan, 2.3, 87k
    Past Caravans:
    2005 Grand Caravan SXT, 3.8 247k miles, Sold
    2002 Grand Caravan SE, 3.3, 166k miles, Sold

  5. #3
    Join Date
    Feb 2011

    I just did this fix myself today. I had a strong gas smell inside and outside the van regardless of full tank, empty tank whatever. No evidence of leaky fuel pump but I could shine a flashlight on the pressure regulator and see that it was dry before starting the van and then as soon as I started it I could see gas around it. Replaced the o-ring per the above instructions and so far it looks dry. I drive 50 miles each way to work every day so I'll find out soon enough if that was my only fuel leak problem!

    Thanks for the clear instructions. O'Reilly is my closest store and they had a Dorman variety pack of vitron o-rings (safe for fuel exposure) that cost around $8. There was one in there that was the right size.

    2001 Chrysler Town & Country LXi 3.8L 162k miles

  6. #4
    Join Date
    May 2012

    Mine is still holding, glad it worked out.
    2001 Chrysler T&C LXi, 2009 Dodge GC SXT - 3.8's

  7. #5
    Join Date
    Jan 2011

    So....its purpose is to "pop off" in case of too much pressure...and thus starting a massive car fire?

  8. #6
    Join Date
    Mar 2007

    Quote Originally Posted by spacecoast View Post
    So....its purpose is to "pop off" in case of too much pressure...and thus starting a massive car fire?
    Yeah, something doesn't make sense... Regardless, prying/flexing the cap tabs back/forth has compromised it, making it more likely for this nightmare scenario. Having seen enough burned vans in the junkyard, I replaced the whole rail - which comes with the cap installed.


  9. #7
    Join Date
    May 2012

    I found the correct name for this is a fuel pulsation damper or fuel pulse dampener, not meant to be serviced.
    Part number is 04591758AA, (You cannot order this) on some of them it has a "do not remove label on them"
    It also has 0063 BT 400KPA stamped on it too.
    2001 Chrysler T&C LXi, 2009 Dodge GC SXT - 3.8's

  10. #8
    Join Date
    Oct 2012

    Yes it definitely is not a "regulator" in the normal sense, and is not meant to blow off either. Frankly I don't see how it would dampen a pressure pulse either, unless it contains an air bubble in normal operation.

    I did my injectors not long ago and stupidly did not also put in the 13th O-ring on this. That was the only 1 of the 13 that was leaking. Murphy's law reigns.

    Replacing the O-ring should be part of the procedure to replace the power steering reservoir and vice versa.
    2002 Town & Country 3.8L AWD

  11. #9
    Join Date
    May 2012

    once I figured out the proper terminology, google came up with more meaningful results, including people fixing it themselves with a fuel injector o-ring.
    At the time I fixed mine, I did not know what the correct term was.

    I like to this of it kind of like a water hammer arrester on plumbing pipes.
    2001 Chrysler T&C LXi, 2009 Dodge GC SXT - 3.8's

  12. #10
    Join Date
    Jun 2009
    St. Cloud, MN

    It's job is to keep the same volume of fuel inside the fuel rail (to stabilize the pressure) while the fuel injectors are opening and closing. That way the computer can more precisely meter the fuel by adjusting the injector pulse lengths with a known, stable fuel pressure.

    The fuel pressure regulator is built into the pump assembly, inside the gas tank.

    I've started to see some 4th gen vans in the junkyard without this pulsation dampener on the fuel rail. Apparently it has been deleted from the rail by the factory design, and possibly moved somewhere else in the fuel system.
    DAN(husband of member STEPHANIE)

    2000 Chrysler Town & Country Limited - Dark Charcoal Metallic with chrome trim, taupe leather interior, loaded. In need of rust repair on rockers and liftgate. Now enjoying the new family mommy-mobile!

    Knowledge can never be wisdom without experience.
    "Your experience is a commodity."
    "Opportunity is not a lengthy visitor."

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