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Leaky Cab


Old 06-19-2017, 06:48 PM
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Join Date: Jun 2017
Posts: 1
Default Leaky Cab

I am chasing a very frustrating problem with my 97 GMC Sierra C1500. When it rains the interior carpet at the back of the inside of the cab gets wet. I read that it might be the gasket around the third brake light so I caulked that - no joy. I covered the truck up with a car cover - no joy, I threw a 2ft wide back carpet runner over the back of the cab that spanned over the topper to block water from going down the back of the outside of the cab - no joy, I have a 5x7 tarp over the cab covering the roof - no joy. What else can I look at? Can't get a shop to look at this issue. Nobody wants to touch this
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Old 10-30-2017, 11:55 PM
Join Date: Oct 2017
Posts: 10

Can someone help? I was wondering where my post was? It is very helpful for those wanting to know HOW TO find water leaks. It was what I learned when I worked for GM as a line mechanic. I had posted it mid day yesterday and it had to be reviewed or approved. But it is still not posted.

Thank you, Tony

Last edited by UV231 Project; 10-31-2017 at 12:03 AM.
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Old 11-03-2017, 06:26 PM
Join Date: Oct 2017
Posts: 10

Misnomerga, Thank you for your PM and interest in seeing my post about how to find your water leak..
I have posted it once more for the second time and again I'm waiting for the Moderator to approve it.
I took a GM training course, decades ago, to learn how to do what I posted.
I hope they post it this time to help you and anyone else who is dealing with water leaks.

Good Luck, Tony
US Army and GM / ASE mechanic retired.

Last edited by UV231 Project; 11-03-2017 at 06:32 PM.
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Old 11-06-2017, 06:51 AM
Join Date: Oct 2017
Posts: 10

When working for Chevrolet; I took a water correction class at a local GM training center. I hope the following might be useful some day.....

I had sent this to "Dave's Garage" on PBS out of Toronto I believe in response to someeone's question and thought I share it with all of you too.

Finding a water leak in a vehicle can be hard. However one does not have to take it to a professional and the correct way of looking for any water/rain leak is as follows:

Things you will need:

1) Plastic Bottle Sprayer (for safety always use plastic – hands will be wet and soapy)

2) Liquid Dish Washing Soap (not dish washer soap)

3) Water

4) Wide Painters’ Tape (1-roll should do – if you end up needing it)

The following is how one finds a water leak on their vehicle:

1) If your vehicle, 70s - 80s, has those vents in the door jam – cover them with tape.

2) Start the vehicle

3) Put Fan and the heater on High with Fresh air. (This has since been corrected.)

4) Open the hood before you get out of your vehicle

5) Make sure your all doors are unlocked and close all doors and trunk

6) Mix in a spray bottle either 7/8 or 2/3 dash washing soap with 1/8 or 1/3 water.
(You want the mixture to be able to spray from the bottle but run as slow as possible on any surface and the reason you mix it now is to allow the vehicle to pressurize)

7) First check the door jam area for sounds of air coming by the door seals – if slightly or none at all move on to #8 if you feel there is a lot of air rushing by the door seal(s) see NOTE below before moving on to #8.

8) Spray your mixture in the area you think is leaking – be patient – and watch for bubbles (making air recycle in the vehicle on high will force any air out of the vehicle where there is a leak)

9) No matter where you feel it may be leaking – always make sure you spray all around the windshield and back glass while doing this process

10) For trunk leaks spray around the tail lights, back glass, and maybe even around the lip of where the trunk lid closes

Lots of times one can look inside the trunk and see water marks which will let you know where the water may be coming from; i.e. your trunk leaks and the water is always in one area – it maybe the lowest part of the trunk or how you park the car and not where the leak is. However if you see a water mark down one wheel-well, which is under the rear glass – then most of the time your leak is the back glass and not your trunk. But keep in mind you may have more than one leak back there so check it all out when doing this test.

NOTE: You might have to tape the door jams – if you hear air coming out from around the door jam and your leak causes lots of water to get in your vehicle - but you are not seeing in bubbles anywhere with your soapy mixture.

Good Luck, Tony
Ottawa, Ontario
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