Bimmerfest - BMW Forums

Bimmerfest - BMW Forums (
-   E28 (1982 - 1988) (
-   -   535i Trunk leak (

TCGSAC 12-11-2010 12:42 PM

535i Trunk leak
I have a 1988 535i that gets a lot of moisture and water in the trunk after a hard rain. I have replaced the trunk seal but that did not fix the problem. Any suggestions? Thank you, Tom

boomhuck 12-11-2010 12:45 PM

Is it getting wet around the tail lamp area?

TCGSAC 12-11-2010 02:42 PM

I have found moisture in the tool area, on the trunk lid, on the carpet and in the spare tire area. I was hoping this was a common problem with this model.

drivinfaster 12-11-2010 05:17 PM

is the trunk aligned properly?? what about any moisture on the back panel??
how long have you had the vehicle?? has it been hit in the back??


TCGSAC 12-11-2010 06:10 PM

Since I replaced the trunk seal a few years ago the trunk needs to be slammed to close it all the way so it seems to be a tight seal. I have had the car for 15 years and it hasn't been in an accident. I'm not sure if it could be from the rear vents on the c pillar or maybe the sunroof.

catso 12-12-2010 09:43 AM


Originally Posted by boomhuck (Post 5689292)
Is it getting wet around the tail lamp area?

This is by far the most common way the water enters the trunk. Remove the rearmost panel and look for evidence of leakage there. Taking the tailights out and resealing them isn't very hard but make sure you find the actual trail of water. the body seam where the rear light panel meets the quarter panel can leak also. You can use some good silicone to seal these areas.

TCGSAC 12-12-2010 09:55 AM

Thank you for the information. I'll check out the tail lights and reseal them. Thanks again for the help. Tom

Hillhippy 06-01-2011 01:31 PM

I have a 87 535is w the same problem. I'm gonna check my tailights as well. I also replaced my trunk seal, you could still almost swim in the trunk at times.

TCGSAC 06-01-2011 02:57 PM

I removed the tail lights and ran some silicone caulking around them. With the heavy rains we had a few months ago it fixed the problem.

Hillhippy 06-02-2011 04:00 PM

cool beans ! i need to get mine to run first

waehrik 11-01-2012 04:54 PM

I know I'm responding to an old thread, but I just fixed a water ingress problem on my 88 535i (no that model matters) and wanted to share my solution.

My old foam tail light gaskets were hopelessly degraded so I replaced them with 3M Strip Calk (yes, I spelled that right) on a recommendation from mye28. It worked perfectly and sealed up great, even under Hurricane Sandy rain. These come in a pack of 60 short strips that can be stacked and twisted together to form a thicker gasket. It's never supposed to harder or dry out, so it should theoretically last forever. Or at least longer than a set of new OEM gaskets, and it's about a quarter the price. Only $16 shipped from Amazon vs $50 for the OEM gaskets.

My trunk seal was leaking too as evidenced by water running down into the tool tray and dripping off the top of the trunk lid. What I didn't realize was that the original seal was supposed to be one piece. You'd never know from looking at my car - it had two perfect cuts on the upper left and right corners along the diagonals, following the seam. I thought there was one piece along the top and another U shaped piece along the bottom and sides. Nope. It was cut for some reason and as it aged and shrunk a little it was enough to let water run in and along the plastic trunk lid liner. This is actually one time I'd recommend something by the manufacturer Uro (gasp, I know.) but I bought one from AutohausAZ for $41. With a valve cover gasket and some crush washers for the oil spray bar I hit $50 for free shipping. The OEM gasket is $75 by comparison. The Uro one came in a nice sealed bag (important to keep plasticizers from evaporating while in storage at a hot warehouse) and is a nice heavy high quality piece. It installed easily and I used an aerospace grade Dow Corning 3145 RTV to glue down to the body. I applied some Molykote 44 grease as a lubricant to keep it from sticking to the lid. That stuff works great on door seals too and keeps them from sticking. I have access to that stuff, but an Autozone RTV and silicone spray should work in their place. Just make sure to use acetone or a strong solvent to clean up the old glue. This is also a good time to take care of any rust you find under the seal. I was fortunate and mine was a Florida car until recently.

Just a heads up in case anyone else found that their trunks were leaking after all the recent rain. For less than $70 you can get it all sealed up again with new parts.

BMWFatherFigure 11-01-2012 07:29 PM

lid alignment very important as a first resort. To help pinpoint any leak: 1) remove all trunk trims. 2) get into trunk with a good torch. 3) starting as LOW as possible with a garden hose wet slowly round the car working your way SLOWLY up. Leak will be obvious when you get to it. Then hope your helper is reliable enough to let you out again.......

Jimmy A 01-11-2013 07:39 AM

535IS trunk leak
Does anyone have a recommendation for a sealant to place under newly installed gasket. Gasket was replaced by body shop repair but due to rust underneath gasket can't get a good seal. BMW dealer said it should just lay in place with no glue or sealant but it still leaks. Any ideas or recommendations for a restoration shop in San Fran Bay area would be greatly appreciated.



catso 01-11-2013 05:01 PM


Originally Posted by Jimmy A (Post 7305651)
Does anyone have a recommendation for a sealant to place under newly installed gasket. Gasket was replaced by body shop repair but due to rust underneath gasket can't get a good seal. BMW dealer said it should just lay in place with no glue or sealant but it still leaks. Any ideas or recommendations for a restoration shop in San Fran Bay area would be greatly appreciated.



You are going to have to fix the rust first in order to get a good seal, otherwise it will continue to aggravate the entire problem; rusty suface doesnt seal well, allows water to enter, creates more rust, etc, etc, etc.

BeaterBimmerGuy 02-02-2013 01:47 AM

9 out of ten times when trunks leak and water gets under the interior carpet its not the trunk seal its the metal that the trunk seal glues onto. I find its best to go deep when cleaning the trunk seal gutter, find all the flaws like rust, well usually its rust. But you have to really scrape away and pick at everything to find the smallest of holes. I sand blast the rusted areas and build it up with putty epoxy then put a couple coats of Rust encapsolator from Eastwood. Glue the seal down with a GOOD rubber cement like Wurth Rubber Cement. Your trunk wil dry up in no time under the carpet takes a LONG long time the carpet padding does not like to give up the water easily.

4dimnzn 08-28-2015 07:50 AM

Jumping into an old thread because I just figured it out after rebuilding the whole trunk lip and seal on my E28 - and water was still getting in there. The problem is the vent on the C pillar. There are 5 plastic grommet inserts that secure the vent panel to the C pillar. Mine were essentially rotted away as well as the gasket that seals in. It was pretty easy to see how water would run through the holes and into the trunk. New grommets, a new gasket and viola. Problem solved.

There was one hair raising moment when I removed the vent cover. I wasn't sure if the securing nipples attached to the cover were plastic or metal. Break those and I could see myself falling onto the garage floor sobbing. Turns out they are metal and were fine.

BeaterBimmerGuy 08-28-2015 11:41 AM

Wow blast from the past here. Deteriorated plastic insert fasteners for the cars color painted air exchange vent cover is a new one to me. Perhaps the car is from a harsh climate. Old 80's BMWs that have spent a lot of their life to all its life here in the Pacific Northwest are probably decades away from having such a problem. I once bought a few Old Bimmers from Southern California that looked perfect when I looked at them in person in California but after I got them home I discovered a lot of the rubber and plastic parts large and small were toast the ones that were not had been replaced. Most of all these parts are extremely uncommon to need replacement on mild climate cars.
Leaks and squeaks are in my little world the most annoying repairs to deal with. Back in the old days dealerships of most all makes had more than a few techs that dealt only with leaks and squeaks on mostly brand new cars, only a few car brands had none of these leak and squeak techs BMW and Mercedes being two of these few. But as the E23 E24 E28 cars got older they started to spring leaks and alot of them. Now around here the most common leaks on any of the E23 thru E28 are and I am sure I will forget to list some. This list is mosly for E28 specific and for trunk only but I do cover "mirror image" items.
1. rusted trunk seal mounts
2. Old windshield and rear window gaskets. I myself denied this a the posibility for years and years yet they leak more than a rusted seal mount frame.
3. Rust around front and rear windows
4. Antennas..This one example has a huge list of possibilities that cause leaks.
5. License plate light rubber broken cracked lenses rust around the mounting point missing and or badly rusted screws and or spring clamp bolts/nuts
6. Tail lights themselves and or the gaskets. Around here the only leaks around the seals I ever seen was due to body work and or accident damage.
7. Trunk lid fit. The E28 has a very weak design as to body strength and a low low speed rear ending can really mess up the trunk lid alignment usual one or both sides of the quarter panel drops a little leaving a gap in the trunk seal area. I saw the guy talking about trunk lid alignment and I agree with some of that but just eye balling the alignment by looking at gaps is all I ever needed.
8. Fuel vapor hoses. While the grommets that the hoses go thru the body into the trunk area is a possibility the usual problem is the hoses themselves. Never actually seen a leak in this area.
9. Grommets that hold the wires that go to the side marker lights.
10 Broken seal of the drain hole inserts in spare tire area.
11. Trunk lock push button seal and the small spring loaded flapper door brokne or missing.

Now with cars that have had body including full repaint work the sky is the limit as to the number of problems that cause leaks. Paint damage around the front and back windows causing rust and leaks is high in the list. Its an absolute must to remove the glass and seals when painting around these areas.
I want to cover a little about the sealing up of the front and rear windows here. For years and years when installing glass and using new or used yet soft seals I never used any kind of sealant however after around ten years leaks did develop. With seals that were questionable and not replaced with new or good I reluctantly used soft sealants, sealants that only from up but not harder like common silicon, this way the if the seal area needs to be worked with again no scraping of any kind is needed only chemical needed to remove the sealant. Reason being is just one small not even visible to the naked eye paint damage thru to the metal will rust and you can't see it till is grows past the seals edge unless you one way or the other push away the seal and look under it.
Its been many years since non DIY people have come to me needing these kind or repairs but all to often owners have made up excuses why there is water in the car but the fact remains a car used properly and without user error like leaving the windows open allowing water in the entire interior should be bone dry. Yes there are many unavoidable situations where water and ither fluids enter the interior but taking proper action the water shouls be gone quickly. But a trunk should always be dryer than the cabin.
Just saw I forget one thing or probably many. I forgot to say usually a rear window leak causes more water to get under the interior cabins carpet, than into the trunk area.

All times are GMT -7. The time now is 02:09 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001- VerticalScope Inc. All rights reserved.