Trunk Leaks & Body Leaks: How to fix them.

  • Thread author Thread author Roadmonster
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Roadmonster

I thought it might be a good idea to post on how to fix trunk leaks,
and body leaks that lead to trunk leaks.

Here's all about how I fixed mine:

Just after buying my '94 RM sedan in August of '03, I noticed that items in my trunk were getting wet after rain, washes, etc.
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I thought it was my rear window gasket, or the trunk gasket. I had my son spray a hose on the car, while I was in the trunk with a flash light. (Not easy for someone with clostrophobia!) I was sure it was the trunk gasket or rear window seal....


It was not either of these...

I went to a glass shop, and they did a free pressure check, and diagnosis. They found that the body seams were leaking on the roof, on the passenger side. Those little plastic mouldings that cover a body seam, from the top of the back door, to the top of the back window.....

They suggested that I go to a body shop... The body shop wanted to pull the plastic mouldings off, re-seal the roof at both joints, and put new mouldings back on, and paint them. Oh yeah....they wanted a lot of $$$$ too.

I was not prepared to pay hundreds of dollars (800-900) to fix this.
I went to Autozone, and got flowable silicone glue.

Permatex "Flowable Silicone WINDSHIELD & GLASS SEALER" part no. 65AR

I made sure that the seams were clean and dry. These seams are the plastic caps that are on the roof, from the back of the rear door jam to the top of the rear window. I have a garage, so I cleaned out the seams really well with Dawn detergent and water. I let the car dry, with an electric heater inside the car, with all windows cracked about 1/4". Make sure heater can't touch anything and burn/ruin it. Once I was sure it was dry, I used "Permatex Flowable Silicone Windshield & Glass Sealer". To allow it to flow, and to keep the mess to a minimum, I used good quality masking tape (the blue kind), and taped around the outside of the seams. This allowed me to sort of "fill up" the seam areas, and keep the silicone off the surrounding paint. After about an hour, I wiped off the excess silicone & removed the tape. I let the car sit overnight with the heater on to speed up the curing process, and get moisture out.

Guess what? No more leak. Cost: under five bucks!!! It took me two weeks to find this leak. Also, it took another week or so to get the trunk dry, with a portable heater in it, while parked in my garage at night. I had a bungee cord hold the trunk lid almost closed, with about a 1" gap each night....(it rains a lot in Oregon).

Hope this helps some other RM owner
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Some other areas the can leak, and look like a trunk leak:

Rear window.

Rear quarter windows.

I don't know if the trunk gasket can really be a big cause of trunk leaks. There would have to be a lot of rust through to get a hole in the trunk lid channel. The metal in the channel is high enough that the gasket shouldn't make a difference in a leak caused by just sitting.

Now, if the gasket isn't seating properly, I can see that it might leak when the car is moving...

Anyone else have a trunk leak experience they want to post?

Stewart
 
mine leaks because the body got all messed up from the rearending. that was my main concern when at the body shop was that I wanted a leak free trunk 🙂
 
Great info Stewart! My trunk has always leaked a little. I just haven't taken the time to trace it down yet. Maybe that will give me something to do this weekend🙂 Thanks for posting!
 
mine leaks because the body got all messed up from the rearending. that was my main concern when at the body shop was that I wanted a leak free trunk 🙂

Well, I suppose that getting rear-ended could also be a cause 😉

Hopefully Matt, that won't be a problem for you from now on.


These cars do have some problems with leaks, and as they age, it just gets worse.


The Wagons have their own leak problems, with Roof Racks, and other wagon specific issues.

Maybe some wagon owners who have dealt with this will post 🙂


Having a body leak makes driving miserable.

I remember all the windows being fogged up and having to warm up the car for a long while every morning before work.

Having to use towels to dry off the inside of the windows every morning sucks.

Then, everything in the trunk would be soaked.
The first load of stuff in my trunk was a DVD player and surround sound system, and all the speakers.
I found all my electronics covered with water. It was not good 😡

Then there's the interior damage and rust that can develop :sad:

Stewart
 
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Great info Stewart! My trunk has always leaked a little. I just haven't taken the time to trace it down yet. Maybe that will give me something to do this weekend🙂 Thanks for posting!

You are welcome JD.

I'm planning to start some "sticky worthy" posts this fall / winter.
Posts that we can all contribute to and build, and then save.
Just to cover the basic stuff with our cars.

I know that we have the "other" forum, and then the "other, other" forum, for when the first one is down....

...but we Buick guys are always the "red-headed-stepchildren" on the Impala sites :blink: ....and that gets old, IMHO.

I think it's time that we can make our own database for the Roadmaster sedans and wagons.

Sure, most of you will go to the other forums too...

...but when there is a new Buick Roadmaster owner out there searching for a place to find info,
it would be nice if we had some basic things here.
Such as:

-opti replacement.
-CAI options.
-simple/cheap performance mods.
-etc...

Stewart
 
My trunk has always leaked a little, too. It only leaks on the passenger side. I thought maybe it was b/c I broke off the little clip that holds the cargo net leaving a hole in the trunk floor(got a little squirly and my sub box went flying...Oops😱 It is now tied down w/ ratchet straps). I think it only leaks when I drive the car when the roads are wet..when the tires are kicking up water. I think, but I will have to double check next time I wash the car.

The said plastic moulding on my drivers side always liked to pop up, but I superglued it down for a quick fix, and it has stayed down so far. The trunk never leaked on the drivers side, though.

Thanks for the very valuable info Stewart! Great example of automotive journalism. This should be a STICKY!
 
When I first got my wagon I pulled out the panel opposite of the spare tire compartment and found about two gallons of water sitting inside.:blink:
Once I drained it, it never filled up again, so I never found if there was a leak or not.
 
When I first got my wagon I pulled out the panel opposite of the spare tire compartment and found about two gallons of water sitting inside.:blink:
Once I drained it, it never filled up again, so I never found if there was a leak or not.


My wagon that I briefly owned had a rotted out spare tire well. I suspect that it had a leak in the roof, probably from the roof rack rails, but I never found the exact location.

Anyone have experience with fixing a wagon body leak?

Stewart
 
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I checked the spare wheel last Sunday in my 1992 Wagon.
Found some acumulated dirt and it was wet ...
I cleaned the area, removed the black protection at the bottom and sprayed an anti-rust & protective stuff.
While it was drying I noticed water was still getting there (was raining outside).
The water was coming from the rear area structure.
I hope it is coming from the rear light seal 'cause if is comes from the roof it will surely be hard to find.
I will keep posted on my leak search !!!
 
I'm not positive, but think I remember reading somewhere that water can leak at the mounting holes for the roof racks on the wagons....
 
I'm not positive, but think I remember reading somewhere that water can leak at the mounting holes for the roof racks on the wagons....


I believe my wagon was leaking there, but never dug deep enough into it to find out for sure.

The spare tire well was completely rotted out on the bottom from it.

Stewart
 
Did some leak check on the Wagon yesterday.

As I do not want to mess with the roof at first I tried to search around the rear light (it looked to me that water was coming from here at first place so ...)



Global view of the rear RH light removed.
Two potential leaks are highlighted.
One other could be at the pop rivet at the bottom. But I did not confirm it even if now it is sealed with silicone as well.



Close view.
The right one has already been "secured" with a white silicone sealant (will be more complicated if your car is not white !!!!).
The left one will be treated with silicone from the inside of the trunk.



View of the leak #2 from inside, BEFORE silicone is put as a sealant.
It is not obvious on the picture but I could actually see the sun light coming through !!!! 😱
This confirms that water could really get through this area ...

I will have to check after some time if water is still entering the spare wheel area ...
 
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Help support this site so it can continue supporting you!
I checked the spare wheel last Sunday in my 1992 Wagon.
Found some acumulated dirt and it was wet ...
I cleaned the area, removed the black protection at the bottom and sprayed an anti-rust & protective stuff.
While it was drying I noticed water was still getting there (was raining outside).
The water was coming from the rear area structure.
I hope it is coming from the rear light seal 'cause if is comes from the roof it will surely be hard to find.
I will keep posted on my leak search !!!

If I were you, I would check that the small drain hole that is under the bitumen mat (should be removed, stupid idea of GMs) is still unblocked.

That is, at least I 'think' that GM puts a little 5mm hole on the bottom for water to drain out. Or maybe it coulda been a previous owner..... If there isnt a hole, perhaps you should drill one? What do you other guys think of that idea?

Anywhoo these wagon spare wheel wells are notorious for rusting and rotting.

Putting a large pair of mudflaps on the rears might not be a bad idea either. Least it will stop water and crap spraying on that part....🙂
 
like this?
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Nice wagon, I wonder whos it is?😛 Just like that though, are those GM logos?

I fitted flaps to my RMW last week, they are even BIGGER and lower than yours!! (note to self, must raise the rears up 1 inch, they rub on the ground when going over speed bumps....)

Oh yeah...nice tint too mate. 30% VLT? How much did it cost you? Mine was $477 CAD. I just got mine done. 5% limo on the rears, 30% VLT on the front. TOTALLY BLACKED OUT baby!!!!:headbang:
 
yes, the hole was present from factory under the black mat (that had a bigger hole from the factory too)

... with mud and some water too ...

In fact the hole area had taken a light hit from underneath and was a bit higher that the area it was supposed to drain ...
I removed the black mat and trashed it.
Took a big rod made of wood, a big hammer and in one shot put the hole down to the level it should have always been 😀

Cleaned the area and sprayed a special anti rust clear protection.

It is fine now but I did not thought about the rear RH wheel splashing water and mud into the hole and into the car !!!!
I will try to add a kind of little flap or vavle below the hole 😎
 
hey roadmonster any chance of getting some pics of exactly where you put the silicon? would be very helpful to at least me
 
Good luck getting ahold of him! Hasn't been logged in in 2 months! He's still alive, as I just got an Email from him.
 
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