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Mercury Grand Marquis Water Leaks



  • I didn't get back earlier because I was traveling, but guess what went in to my Marquis and the lake was there too.
    I had left the carpet lifted since this all started and did not put it back together, I had it lifted off with some pieces of wood strategically placed to keep it off the floor. Well the main leak is sealed because this days are raining constantly and at one point I stayed inside the car while it was raining and saw water coming thru the side corner right at the end of the relay panel, but very slow so I'm puzzled by this new one. Like you did I 've tried the undercoating stuff but then again the water was not coming in thru there. I will wait till Saturday and try to
    check behind that fender liner to see if there is another opening that I can cover with silicone. Strange thing is
    I replace a broken electric antenna 4 month ago, maybe that had something to do with this, although I 've checked all
    wiring entrances into the cabin.
  • I have a 97 Crown Vic that is having the same problem. I have had the seats and carpet out so many times I am sick of it. I am in the process of tracking down the leak as described in the forums. Does anyone have pictures of where this stuff is? Looks like a piss poor design flaw by Ford. Oh yeah, the car has been recalled for a faulty cruise control that may cause it to catch fire. I would only be so lucky. Actually it is a nice car other that a mobile mold and mildew experiment. :
  • I found out where mine was leaking,also have seen this on other forums where this problem is mentioned. If you pour water into that black tray under the windshield you should see a steady drip down the outside drivers firewall. If you follow the drip it ends up on a rubber seal around the cable for the cruise control. My 97 crown vic had a crack in this seal. The water follows the cruise control cable into the car onto the carpet creating a flood if it rains for a long time. It took me several times pulling the carpet out until I found it. Once you find out where the water comes in you can seal the leak either by putting rtv sealent on the crack in the rubber grommet around the cruise control cable,replacing the cable grommet, or sealing the plastic tray so the water is directed to the side of the engine compartment down behind the front wheel. If you do any of the above you should stop the leak. If your windshield is leaking then all bets are off.
    Another way to find the leak is to shine a very bright light in the firewall area and look from inside fo the light with carpeting removed.
    Good luck I stopped mine.
  • Thanks for the info. My problem is on the passenger side, but I should be able to track it down like you described. I have the inner fender loose and blower motor out. A local glass place told me the screen below the 1st plastic tray leaks a lot. I bought a tube of the good urethane sealant that they use. He cautioned me about RTV unless it doesnt contain acetone. Will eat up metal... I am going out now to putty the crap out of everything that looks like it needs it. Will let you know.
  • Be careful that you don't seal something that is designed to drain the water.
  • Thanks to everyone for the advice. I believe I found the problem. Inside the inner fender well there is a little flap that covers the exit drain from the case. If you remove the flap there is a foam gasket between the firewall and the plastic ducting. As a mechanic told me, foam is like a sponge and why would you use a sponge as a seal? It will shrink and draw water eventually causing a leak. If Ford really did have a better idea they would use rubber gaskets. I guess there better idea is to rip off customers. Anyway I used the Urethane that I got from a window installer and sealed all the way around the hole, I am going to try running the car without the little flap and see if it is really needed. I don't believe so. I also used the Urethane on the screened piece just below the window tray. Ran a lot of water on it and no leak, at least not yet.
  • Just Bought 96 Grand Marquis Has 166,000 Km In a very good shape.
    I found that the pass.side floor is wet, so I thought they had cleaned the car before selling it to me and this part was still wet so I dried it by putting clothes under the mat and I would change to a dry clothe every couple of days.
    So far It's drying up, but I'm afraid It's a start leak even though it rained lightly for a whole 2 days and It's only damp a bit.

    It took a whole gallon of a premixed coolant before it stopped losing some (Level).

    Other than that I'm very much enjoying my new ride.

  • ralkaralka Posts: 72
    pull the carpet back on the right front floor and run water over the windshield. than look to see if water is coming out of the bottom of the hvac or to the side of the case, or from higher
  • I have a 97 Crown vic that leaks on both sides. I performed the seal the hell out of the fresh air intake and had no luck.

    I pulled out the carpet and loosened the sound deadner on the firewall and had the wife start running the hose. I found the leak on the drivers side was coming from the grommet on the hood release cable that passes thru the firewall. It was cracked.

    The passenger side was the grommet on the round bundle of wires that runs thru the firewall right under the heater box. The grommet is the larger one, about 1.5 - 2 inches in diameter and has a bunch of wires going thru it. It looks like it either shrunk or it wasn't spec'd right from the factory. What a pain to find. Hope this help some folks. Good luck.
  • felhetfelhet Posts: 1
    I never had a problem with my 96 until I moved to Texas and experienced the torrential rains there.

    I read the posts on this site and decided to investigate myself. I used to have PUDDLES on both driver and passenger sides in the front and back.

    I ended up removing the plastic cowl cover under the windshield and then the wiper tray which holds the wiper motor and the wiper mechanism. You have to take off the wiper arms themselves to do this.

    The wiper tray has channels for water to run and in the middle there is a plastic/rubber flap for the water to collect and drip down a "chute" down the middle of the engine bay and firewall. My wiper tray was COMPLETELY clogged with dirt and leaves at the mouth of the rubber flap. I vacuumed all the dirt out and cleaned all the little crevices and replaced the wiper tray.

    I also siliconed the heck out of the fresh air intake on the passenger side since the gasket shrunk like everyone else. And I siliconed the heck out of the cables going through the driver's side firewall.

    So far I have had NO problems. I did all this 8 months ago and we have had some hard rains since then.

    Hope this information helps. Let me know if there are any questions.
  • cathiewcathiew Posts: 1
    I have a water leak - passenger side - not coming from windshield, no debris clogging cowl; not coming from heater fan motor; dealer says leak is a common problem most likely coming from windshield wiper motor cowl and can repair for $400 -$500. Any ideas where else it could be coming from?
  • afretafret Posts: 2
    My wife & I inhereted the 96 Crown Vic from her parent's estate....found that we have a water leak. Only on the passenger side--but BOTH front and back floor boards are wet after a hard rain. I read about 5 pages of posts on this discussion...but, haven't seen comments about both front and rear floor boards becoming wet. If the water is coming in through the firewall (as it seems with most of these posts) can the rear floor board become wet?

    BTW....took the car to the local Ford dealership. Lets just say they found nothing and had only wags at the potential problem.
  • afretafret Posts: 2
    Took it to the dealership (again) to give them more time to troubleshoot. They found the problem...they said it was a hardened door seal (NOT--notice my sarcasm). A friend suggested an auto body shop as they deal with things like this on a regular basis. So I did...they called within a couple of hours and said that they wiper tray drainage seal was bad. $125 later...and numerous rains, it's dry!
  • My 2006 Grand Marque leaks rain a lot of water on the right rear passenger side.
  • Does anyone know of a fix for this problem.
  • I purchased 2008 , used, from dealeship-the dr door was maladjusted-rubber sealant on windshield-front cowl maladjusted --Dealer said nothing was wrong with car at sale..--whenever I use wipers and washer the cabin fill with fumes from washer fluid. Also ac never gets cool on 80 degree days with 3 people inside. 2nd dealership charged me about 800$- they readjusted dr door and trunk lid--watered down washer fluid so as not to have a scent--completly ignored me when i suggested washer fumes leaking into cabin and lack of ac cooling was the same problem--lack of sealing. Also --when stopped behind idling cars -there exhaust is overwhelming.. also-the windshield fogs up on most rainy days. I do not use washer when cleaning windshield because of obnoxious fumes leaking inside. I must handwash/clean. Service-depts really are not astute to troubleshoot and fix-- A good dashboard/firewall tech could easily detect and fix this issue. I am sure there is at least one service dept with one qualified service rep in the Wash.,,DC area. I will continue on to a third service dept --just maybe I will luck up and have this one thing fixed and resolve all the above issues. I hope this letter helps you to refine and define your issues with water leaks or any leaks that brings in fumes- leaks ac air cooling, winter time heating not warm enough, foggy windows. thanks for reading id: sorrymodelyr08
  • faxjaxfaxjax Posts: 1
    I too had the infamous water leak on the passenger side.
    The passenger side wheel well needed removed then I could see the 1 bolt and nut that allowed water to run back in the cabin. The bolt was just under the Heater box assembly. Just put a silicone around it, and around the rubber flapper hole in the firewall. No more leak.

    Thanks to all that posted their scenerios This helped track down my issue.
  • perry16perry16 Posts: 2
    with 50 yrs experience i never saw water go up hill 99% of the time it is drain holes that are clogged under windsheild cowlings
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