98 Silverado interior water intrusion

[inthechateau]

So after getting power train on my Project truck going I start on interior. The entire passenger side carpet insulation is soaked. Pulled carpet out and it has been wet for a long time. Rust starting with bubble in the floor paint. Wondering are there any common areas to look at for water intrusion on these trucks? Getting it all dried out and washing carpet while it is out. Hope to get wife to soak cab and windshield area with hose while I look under dash on inside for source of leak. Appreciate any input.

 

[Big D]

Are you Sure its not your heater core leaking?

 

[bluex]

Heater core, windshield or the hvac inlet duct in the cowl.

If it's the hvac duct you have to pull the wipers, the black trim an then on the pass side you'll see a panel seam sealed to the cowl. Cut the seam sealer with a razor an remove that panel. You now have access to the inlet for the hvac. The foam tape dries out an allows water to enter. Remove the tape an silicone it up, inside an outside that duct. Silicone the panel back over the top an then use silicone in the cowl trim screws as well. One of them is directly over the inlet. One way to know if it's the inlet or not is to put it on recirculation. If you see no leaks then reseal that inlet opening.

 

[bluex]

Here is a thread with pictures about this issue.

http://www.gmt400.com/forum/showthread.php?t=15928

 

[someotherguy]

Didn't go through that 6 page thread but the offending screw in many cases is the one that sits directly over the fresh air intake in the cowl - and can be accessed by just removing the passenger side cowl corner trim piece:

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Richard

 

[bluex]

You posted that same info in that 6 page thread. The leak is sometimes larger than just that screw, like it was in my case. From the op's description it sounds like his is more than that as well...

 

[sewlow]

How's the seal on the 3rd brake light? That's where mine was leaking. PITA to figure out as the water ran to & puddled in the passenger side footwell. Don't know why, but the driver side was dry. Weird.

 

[inthechateau]

Thanks for the info. Defiantly not coolant, clear liquid. I'll pull the cowl off tonight, since I have the carpet all out won't hurt to go crazy with a hose to confirm it. I'll look at that 3rd brake light too, going to be pulling the head liner next as it was a smoker truck and smells to high heaven like an ash tray and part of it is sagging any how. Be a good time to wire my windshield visor lights too.

 

[sewlow]

A compass/temp mirror, too! Hehe!

 

[inthechateau]

I can now see a line where the water is comming in next to the blower housing. Looks near the top of the firewall at the hood hinge area. Can't get into it with out pulling the entire blower housing. This sucks.