Windshield - Water Leaks

Greetings!

I'm new to this forum but I can identify with many of the observed problems with the 1998-2004 platform. One problem I haven't seen posted yet is a known GM problem with the windshield leaking immediately above the rearview mirror. The water enters under the windshield trim strip (usually as a result of having the van washed at a car wash) and follows the channel down either "A" pillar and into the channel under the kick plate where a number of wiring harness items are located.

In my case the problem surfaced just after the van went out of warranty and caused the power locks to only work from the passenger side, not the driver side. Also, the carpet was wet from time to time under the driver’s side removable mat. First clue!

Testing indicated that there was a 'short' somewhere, but I gave up and took the van into my ‘trusty’ GM Goodwrench dealer who charged me 1 hour to fix it adding a notation on the work order that I had to find the source of the water leak, which might involve removing the headliner. Second clue!

I searched the NHSTA web site and found a GM Tech bulletin that outlined the problem as a poor seal of the windshield during manufacturing. However, the tech bulletin recommended that the roof be removed and the area fixed via a body repair in order to correct. No wonder the dealer never mentioned this, HUH?

I’ve got a whole list of items fixed in and out of warranty, some in this forum now. I will share the ones I have experienced that I have not seen with appropriate fixes.

Thanks forthe info.

I have a 2003 Montana and I have noticed water dripping above the rear view mirror where there is a light assembly.

The van is still undr warrantee, about 3000 mi left.

Can you direct me to the tech bulletin.

Thanks forthe info.

I have a 2003 Montana and I have noticed water dripping above the rear view mirror where there is a light assembly.

The van is still undr warrantee, about 3000 mi left.

Can you direct me to the tech bulletin.

Sorry, I couldn't find the bulletin I mentioned. I had a .PDF of it, but have misplaced it.

If you have the embedded antenna in the windshield, look at the windshield from the outside, more specifically dead center at the roofline. The wires attached to the antenna enter at this location. The blackout applied to the windshield will be peeling away. I've seen a number of vans with this problem. This is an indication that the seal has failed and will need to be re-done.

A glass shop near me tells me that they fix many of these van windshields, usually for the problem I have outlined. However, roof rack mounts (if so equipped) can also cause water to enter the cabin as well.

I had a leaky windshield too. It just cost 4998 to cut off the entire roof and all rusted pillars. Dont wait too long! If it is under warrenty, FIX it! I got lucky and my insurance paid for it since I had a windshield replace 5 years ago and they said the guy forgot to prime the metal during the replacement!

My van started leaking a short time ago, and when I started to look around , I discovered a rust spot on the roof where the winshield edge is. Upon further inspection, I discovered a hole under the rust. This problem has been discussed in the Venture forum, and some of the ideas were that the leaking could also be caused by the roof rack,(if the vehicle has one,) and the internal windshield antennae.

I have replaced a number of these windshields, and in the process I have found lots of reasons why they would leak. Some due to the previous replacements as well as factory installations.

The antenna and it's wiring are all inside the vehicle, and unless the wiring got caught in the urethane during installation, it would not be the problem.

I have seen many of these w/s installed from the factory with nowhere near enough urethane, often resulting in leaks. (And it is a serious safety concern... wonder if they have ever been sued?)

Other possible problems:
The glue may be located too high, and is stuck to the moulding instead of the glass. (the moulding is decorative, and has no value as a seal). Corrosion may be causing the adhesive to let go of the pinchweld, incorrect glass preparation or incorrect glue may have been used... there are tons of possible reasons.

Best way to find a leak...
Get a can of aerosol glass cleaner, and spray a thick layer of foam around the glass on the outside, covering the entire moulding. Take an air blower around the inside of the glass. When it blows a hole through the foam you have found your leak. Use urethane and repair it from the inside, not silicone.

....I have seen many of these w/s installed from the factory with nowhere near enough urethane, often resulting in leaks. (And it is a serious safety concern... wonder if they have ever been sued?)....

I agree with you.

Ours probably started to leak after going through a Petro Canada car wash that stopped prematurely. However, the overhead brush roller sat there beating on the top of the windshield for what seemd like an eternity.

Within the next year or so I noticed that the blackout (top, dead center) painted on the windshield (I think the blackout is designed to obscure the pinch channel mount and urethane) had started to seperate or flake from the windshield. I've noticed this same problem with a number of vans.

Guess getting beat on in the car wash (and it was forceful too) was enough to start it leaking. The following year we took the van cross country and had it washed each morning before heading out on the road. By the time we got home the carpet was wet on the driver's side only. Later caused the power locks to stop working as water tricked down into the channel on the driver's side.

Seems GM is aware that the windshield may not be sealed properly on many vans produced, but has chosen to ignore it.

Sounds to me like you have the "more glue on the moulding than on the glass" problem.

Quick solution is to get up under the headliner with some urethane and pump the space between the pinchweld and the glass full.

I strongly recommend using Essex U-418 urethane for these types of repairs. U-418 contains all of the adhesion promoters necessary for good adhesion to unprimed glass. It is available from most glass shops or suppliers for about $10 per tube. (Don't cheap out here)

I should clarify something... there is U-418 and U-418HV. The HV will be very difficult for you to work with.

Sounds to me like you have the "more glue on the moulding than on the glass" problem.

Quick solution is to get up under the headliner with some urethane and pump the space between the pinchweld and the glass full.

I strongly recommend using Essex U-418 urethane for these types of repairs. U-418 contains all of the adhesion promoters necessary for good adhesion to unprimed glass. It is available from most glass shops or suppliers for about $10 per tube. (Don't cheap out here)

Apple Auto Glass out here in Oshawa is familiar with the problem. They have sealed tons of these windshields in the last three years. I had considered taking the van in and letting them do their thing.

They mentioned that they might have to replace the black molding trim in order to re and re and properly seal the windshield, AND they tell me they could break the windshield taking it out due to age and stress points in it now. So, I've held off. I guess I could try the sealing from the inside??, but that stuff is messy black and gets on everything if you are not careful. The interior is dove grey so you can see my apprehension rising.

Do I attempt this or let them do it?

Do you have an idea of approximate cost (labor-wise, etc)