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Mercury Grand Marquis Water Leaks

I have a 2002 Mercury Grand Marquis that leaks water on the driver's side whenever it rains. I have spoke with several mechanics and took it to the auto shop but no one can find where it comes in. I have sprayed water on the windshield and still couldn't find the leak. Has anyone else had this problem???


  • Hi! Go to the post about the water leak on the 98 to 2002 Lincoln town car. This is about the water leaking on the passenger side, but will probably be the same problem which is a gasket seal under the black plastic tray that is under the black plastic cover that is under the wiper arm. Bill E
  • 2006gm2006gm Posts: 1
    our 2006 grand marquis leaks water that pools on the floor in the right rear. :mad:
  • Karen_SKaren_S Posts: 5,092
    Here is a link to that topic in Maintenance & Repair. Water Leaks-How to fix and find
  • Hi Karen! My Lincoln was a 2001 and the repair cost at dealer was $195 but your 2006 should be covered under warranty.
    Your dealer will know what to do as they have had plenty of Crown vics, Merc Marquis and Lincoln Town Cars that leaked1

    Water runs through the bad seal, then down under the front carpet and then to the back carpet. The first time I noticed it the front didn't seem as wet as the back, but found out it depends on which way the car is sitting as the next time it leaked in both front and back A LOT! Bill E
  • leovicleovic Posts: 2
    Hello, I have a 2000 Crown Victoria. I've just found that the carpet underneat the passenger side is completely wet (but not damped on the top)...the carpet and floor mat in front of the back seat (passenger side) are completely wet. The car is kept in a garage most of the times. Do you think it's the same problem? I have the impression that the water is coming from underneat the car...bellow the back seat of the passenger side. Thanks a lot for your input!
  • beaton38beaton38 Posts: 8
    Hi! I'll bet it is that bad gasket and if your car sat outside more you would find that the carpet would be soaking wet after a big rain.

    Water runs through the bad seal, then down under the front carpet and then to the back carpet. The first time I noticed it the front didn't seem as wet as the back, but found out it depends on which way the car is sitting as the next time it leaked in both front and back A LOT! Your Ford dealer has probably had dozens of these, so they will know of the fix. Bill Eaton
  • leovicleovic Posts: 2
    Hey Bill,

    Thank you so much for your reply. I'll take the car to the dealer...hopefully the repair won't be expensive! I'll post the outcome.

    Best regards, Leo
  • lovemymgmlovemymgm Posts: 1
    My 2001 merc marq leaks on drivers side floor have change heater core, & front winshield (had a small crack in it) and still have the leak please somebody tell me what the real problem is!!!
  • beaton38beaton38 Posts: 8
    Hi! Most of these develop your type leak. Usually it's on the passenger side, but some leak on the drivers side!

    See my previous posts: the dealer has had dozens of these so he will know what to do. My 2001 Town car did this and the dealer said 'that's a common problem'. Cost fixing it was a little less than $200. That was in January and it hasn't leaked since. Bill Eaton
  • Hi,
    Our Merc Marq leaks on the drivers side. It has been to two different dealers and so far it has been a BIG waste of money at both places and we still have the leak. We are in Winston Salem, NC. Our windshield was replaced, rubber in side windows have been replaced, Seals have been replaced, black plastic tray around windshield wipers have been cleaned out. Love the car but ready to throw up hands. Did you get yours fixed and what was the problem????? Thank you.
  • beaton38beaton38 Posts: 8
    Hi! If you can figure out how to get to the past posts there were several who had the same problem with Merc, Linclon TC and Ford Crown vics.

    Basicly....there is a gasket that is behind that plastic tray under the windshield wipers. That gasket goes bad and when it pours rain.... it leakes. It may leak more one time than another as it depends on how the car is sitting.

    Dealer replaced that gasket with silicone seal and it has not leaked yet. Dealer says it's a common problem. Cost was about $190 which included the dealer keeping the car for three days and drying out the carpets. Bill E
  • patpat Posts: 10,421
    If you can figure out how to get to the past posts...

    The page links on the gray bar above (and also below) the list of messages will help display the previous messages within a discussion. And the keyword search on the left side of the page will help find other discussions and messages. Hope this helps! :)
  • Sounds like you need to watertest the car yourself. Hopefully you know a little about how to remove interior trim. Its easy . Pull the side plates off and lift the rug up in the front. Park the car the way you normally do ..uphill downhill rightside higher...left side higher. Slide the seat back so you have lots of visibility on the floorpan. Dry it out so you dont get fooled by existing water. Heater will work fine. Get out the hose. clean the hose so not dirt is on it ..dont want to scratch the paint. Approach the car from the pass rear and set the hose on the roof. Put a towel down so the metal hose end doesent scratch the paint. Put something like a block of wood on the end of the hose so that it stays there. turn on the water so it rolls towards the front and down the windshield...and over the front and hopefully rear door. Let the water run. Be patient. Get out your flashlight and open the pass front door so you can observe any water trailscoming in on the drivers side. If your sight is bad puff some baby powder over the floorpan and up the sides . wetness or trails will be more obvious with the powder. Eventually the leak will show itself. Let me know what you come up with. Sounds like we will have to figure this one out ourselves since the dealer doesent know how to fix leaks. I do. All other replies in this section tell how to fix the passenger side leak but they dont apply to a driver side problem. Write back with a full explanation of what you come up with and I will help you figure this out . Been doin this 25 years.
  • I have a '97 Crown Vic which use to have a water leak on the driver's side carpet. I had to remove the wiper arm on that side and lift that plastic tray up and clear leaves and other debris that had plugged a weep hole. I used a long piece of plastic (12" cable tie worked for me) and swished it around until water began running out behind the drivers side front wheel as it should. I have not had a problem since and it has rained cats and dogs here on several occasions. The whole procedure takes about an hour as there are five or six screws to be removed and a plastic snap off rivet to be removed but you only have to do this once. Hope this helps.
  • I came across your post looking for ideas on how to fix mine, and sure enough I've seen here that a lot of folks are with the same problem. I know were the water is coming in, right thru the lower plenum (I think that's how is called) which indeed is the lower portion of the outside vent. I did the clean up and check up of the gasket but it looked good to me I applied a bit of plummers putty to the
    far right side of the gasket to cover every gap, and still it leaks when I put the hose like you said on the roof towards the right side of the windshield. My idea is if there is a gasket right at the firewall were it meets the
    plenum inside the car, how can I replace this without messing to much withtall that plastic, my Grand Marquis is a 92 and after all those years things can get pretty brittle.Thanks for your help.

  • Hi Mike! I think the only sure way to stop this leak is to do what the previous posts say. The dealer did my 2001 Town Car, but charged me a little less than $200.

    I think Ford Motor Co should have had a recall on all these Ford Crown Vic, Mercury Marq, and Lincoln town cars to fix this problem but they have not! Bill Eaton
  • Hi Bill;

    After my first posting, I did called the local Ford dealer in which I have a friend working at the parts dept., and asked him if he had heard of that problem, he said no but in fact he has a 92 Marquis as well and it leaks at exactly
    the same place, but he did not mind as long as it drives good. After checking for the gasket he said the same thing mentioned here, they sell the entire plenun for $65.98. So
    I will start today by taking that air intake out and prepare the gasket myself with plummers putty, and observe
    how it behave before closing that area again. I will also look for a drain tube that should be somewere around the A/C plenum at the engine side firewall to see if it is clogged., By the way do you know were it might be?. Thanks.
  • That black plastic tray which is under the plastic cover with the slots and holes for the wipers was filling up with water on my 97 crown vic. After I got the leaves and other debris out of it I felt a small round hole at the bottom right side.This is the weep hole that I referred to in my previous post. I swished a 12" cable tie around in it and water immediately began draining behind the drivers side front wheel. I put it all back together and have not had a problem since August. I have no idea why the gasket should have to be replaced if the water does not overflow as it is draining properly.
  • Last night I pulled the wipers and plastic cover (everything clean under there), pulled the intake at the right side, which by the way was perfectly clean inside that
    housing. I did find the weep hole and make sure was not clogged because I swished the area with the cable tie.
    After checking the gasket I've decided it was deformed mainly flattened, so I removed it and applied a thick bead of silicone and tight everything back. I haven't tested out yet, and it's sunny today, so later on today I'll spray some water on that area to see if it made a difference.
    Will post result, but still can't understand (as vernes97
    mentioned on previous post) if nothing is clogged and water
    runs free on that area why water sips thru there and ends up
  • I hope yours is fixed. A mechanic at a used car dealer told me that they routinely fix interior carpet leaks by doing just what I did. MY 1996 E350 was doing the same thing last year but was much easier to fix as there was a foot long hose that drained the wiper tray into the inside fender area.It was totally clogged with leaves and stuff. I didn't have to remove anything as the hose was right out there in plain sight and easy to remove.
    One thing I didn't mention about the crown vic is that I drilled a small hole just to the right and of that weep hole after all the water drained out in the plastic tray as insurance. The hole was in the side rather than the base of the tray. My carpet has stayed dry after numerous heavy rains.
    Good luck and best wishes.
  • I've been checking every day for leaks after my fix and so far so good, and it did rain quite a bit this morning.
    I still have the carpet to one side to allow more time to dry since it was pretty wet before I worked on it. Hopefully it will stay that way. Thanks for the good advice.
  • Just to update, two days later it rained cats & dogs and unfortunately it leaked again. Back to square one, pulled again that plastic cover on top of the fan intake and the silicone I've applied was not that thick, so I clean everything up again and this time I've made a thick strip of plummers putty and sealed real tight. I did this just to
    see if it really stops the water. Once I'm sure I will prepare a rubber foam gasket of a template I've made from the plastic cover. So far with the hose it doesn't leak, but nothing like a good'ol Florida rain. Will keep all posted.
  • I'm starting to think that maybe the idea isn't so much to stop the leak as it is to give the water another destination like I did when I drilled that small hole in the side of the black plastic tray to the right of that weep hole. Still dry after 3 days of rain and original fix done in August. As I mentioned before my 96 E350 has a hose hooked up directly to that tray going right to the inner fender and right to the ground- you can see it run out when the van is moved.
    The whole thing looks like a case of bad design with the crown vics and GMC's-sorta like having to close the barn door after the horse is loose.
    Good luck and best wishes
  • Well I don't want to get you tired but again it rain and guess what, it leaked at the same place. So last Saturday I just couln't understand why if everything looked pretty sealed it will still sips inside thru the lowest bolt of that black plenum inside the car, so I pulled out the right front tire and moved the inner plastic fender just a bit enough for me to see another angle of that peep hole. At the same time I have my son blow air with the compressor hose just where I was seeing the water coming in, and sure thing it was around the peep hole, not in the actual plenum peep hole. So I spread a bead of silicone around and put everything back. Hopefully this time it'll do the trick but I haven't tried out yet, I will let it dry really good.
  • I never removed that black plastic tray. Once I seen it all filled with water I started looking for the drain so I never got as far as the gasket under it. I probably just got lucky by clearing that weep hole out and going no further. If yours keeps leaking I would either park the car with the front facing downhill,or drill a hole under the carpet to let the water out. Or,if all else fails, take it to the Ford stealership and let them do it. If it wasn't for this leak problem these are pretty good cars.
  • I think I 've finally got it, it rained last night and is all dry inside, so the problem was that I was looking in the wrong place all this time. I was already considering throwing a gold fish and have my own fish tank in the passenger side of my Marquis.
    Really it has been an excellent car and still is, I just didn't wanted to give up on him.
  • I'm glad you were able to figure it out.
  • Reading the thread above has helped me some but I still have a question. I have 96 Marquis that had a long history of water getting into floor. I bought the car and right away noticed water in passenger floor. I took windshield wiper off (flex arm back and pry out sliding lock underneith). I took right side cowl plastic grate cover off ( four screws). I then took screened cover dam off of intake plenum box (three bolts). I found the gasket under the screened dam for the intake plenum box was brittle and broken allowing water to pour down into the intake box. The intake box has a door half way down that allows air into the car. At the bottom of the intake box is a hole facing toward the front passenger wheel that drains water if it gets in. I poured water into the intake box to make sure that the drain was not plugged and the water ran free. I cleaned some minior leafs, tree needles and etc from the area along under the cowl. Water that goes through the plastic cowl grates must run off the side of the fire wall on the right side of the car inside the fender. I made a new gasket for the air intake screen and put everything back together. I haven't had another problem yet. However, I noticed when it is all back together that if water runs down the windshield onto the plastic cowl. The cowl is slopped towared the windshield wiper drive shaft and that water then must run through the cowl grates that are "directly over the top" of the air intake screen. Maybe I'm stupid but this doesn't look like one of "Fords better Ideas". If the drain at the bottom of the air intake plenum parially plugs for any reason just normal rain would cause a leak inside the car. I'm thinking of modifing the cowl by closing off the open grate in that area and installing a drain in the cowl to divert water to some place other than the air intake. Any thoughts??
  • Finally- after almost 3 months- I got in my 97 Crown Vic and you guessed it, Lake Okeechobee on my drivers' side floor. If any of you guys that tried to fix it themselves had any suggestions to get it right the first time .What would you do? Right now I'm leaning towards taking it all apart,putting a new gasket in there,and improving the drainage systen in there somehow. I got it in my garage right now after considerable effort and pulled the wet carpet and hung it to dry. It's 4:30 PM and I'm not gonna do anything 'til tomorrow so I'm open to suggestions 'til then.
  • I will reply to my own post. Only 1 thing changed since I cleaned out that drain hole back in August. I got that underspray-RUSTOP- done last week. After I cleared out that gooey, vaseline-like stuff out of the drains water began to run out behind the front tire like it should. Now I just have to wait for everything to dry out. While I was under that slotted cover I drilled another hole next to the one that was already there.I really thought that this was fixed back in August.I guess it just goes to show you that bad things can happen while you're trying to do good things.
  • 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)...how 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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