Help needed with Water Leak

[Ironhead]

Hoping someone in the group's been down this road before, and can give me a tip.

Sometimes, I get water on the passenger side floor. So far, I've cleaned out both the cowl drain assemblies on the firewall. I've removed the plastic grill pieces under the wiper arms, and checked for debris in the cowl air vent area. And lastly, I took the little rubber elbow off the heater/AC drain on the firewall, just below the heater hoses.

For a while, I thought I had the problem solved, but then I washed the truck yesterday, and some water came in. Do not want a rusty floor or cab corners, so I'm hoping one of you guys can chime in with some suggestions.

By the way, it's a 98 Silverado std. cab with AC.

 

[tunedbytuna]

I have the same issues on a 94 and a 98. One has minor rust along the top edge of the windshield, just enough to let a little water get in. The other needs new gaskets around the door. If you can, sit inside and have someone cascade water from the roof and look around. It could come in anywhere, and travel along the path of least resistance. My solution is to keep them in the garage when it rains until I have resources to fix them.

 

[volunteerff21]

Check this out. (scroll down the thread a bit)

http://www.gmt400.com/forum/showthr...uot-Black-Fox-quot/page90&highlight=black+fox

 

[Ironhead]

Hey thanks! Gonna look into this on my truck.

Forum is a great resource.

 

[kennythewelder]

Here is what has worked for me in the past. Take a garden hose, with nothing on the end of it. Get a buddy to help you. Turn on the hose so the water is flowing out in full flow but at low pressure. So just crack open the water valve. The water should be flowing out about 2 inches from the end of the hose, not spraying across the drive way. Get inside the cab with a flashlight. Close up the doors, windows, ect. and have your bud pass the water hose along the suspect area. When he passes the water over the leak, it will show itself. Once you find it, you can fix it. I know this is a very simple process, but sometimes it is the simple things that work best.

 

[twomanymontes]

Here is what has worked for me in the past. Take a garden hose, with nothing on the end of it. Get a buddy to help you. Turn on the hose so the water is flowing out in full flow but at low pressure. So just crack open the water valve. The water should be flowing out about 2 inches from the end of the hose, not spraying across the drive way. Get inside the cab with a flashlight. Close up the doors, windows, ect. and have your bud pass the water hose along the suspect area. When he passes the water over the leak, it will show itself. Once you find it, you can fix it. I know this is a very simple process, but sometimes it is the simple things that work best.

I agree, It's what we do at work. Sometimes it takes a while to spot, but it does work.

 

[Ironhead]

Since my first post, I've taken the rubber "gutter" strips from both door openings, and cleaned them out, as well as the metal underneath them. My next step is to remove the plastic cowl vents (again), and carefully look for any open seams or breaks in the sealing strips. These ideas came from the great suggestions in the thread, and I'm grateful for the help.

With Christmas, and the lousy weather lately, I have not had much time to work on this, but as soon as I can, I'll report out. In the meantime, it does not seem to leak at all in heavy rain, just when I used the hose to wash the beast.

 

[Ironhead]

No leaks lately, but I was just thinking about the problem, and took another look. The plastic vent trim pieces at the base of the windshield are held in place with sheet metal screws, which seem to go right into the cowl of the truck. I wonder if water can run down those threads? To find out, I plan to remove each of those screws, put thread sealer on them, and re-install. I will, of course, then wash the truck, and see if any water enters the cab. My floors and cab corners are mint original, and I do not want a rust issue.

Just wondering if anyone else has been down this road?

 

[Ironhead]

Removed the sheet metal screws, and the plastic cowl vent trim pieces. Put RTV in each screw hole, and on the threads of each screw. Re-assembled the whole mess. Got out the hose, and washed the truck. And, at least for this time, the truck stayed nice and dry inside.

Hopefully, this was it.







re

 

[88GMCtruck]

There is only 1 screw that is over the HVAC intake in the cowl that water can run down, the rest will drip into the cowl which all the water from the windshield will run down anyway and they drain in the corners.

I went through everything you can think of to re-seal my truck - cleaned the cowl, sealed the HVAC screw, replaced windshield, new cablight bases and lenses, then completely re-seam sealed the cowl/cab/firewall seam and inside the cowl with flexible rubber sealant.... It was a lot of work

I found that my leak was so subtle I couldn't easily replicate it and figure out where it was coming from. I used soapy water outside and compressed air inside the truck. If you can pressurize the cab you can identify the water leaks easier.