Another leak question . . .

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SgtPreston

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My 1994 Yukon SLE 4x4 (just purchased) went through the car wash to check for leaks - seemed to be tight around windows, doors, etc. so I was a happy camper - until I took the floor mat out to clean and found the carpet wet on the passenger side. Pulled everything out and noticed the carpet slightly discolored so it has leaked in the past, but fortunately no rust. After reading all the posts here I started on the checklist of possible leak sources and eliminated the heater coil as I had just replaced it, besides the leak is just water (no antifreeze), removed the windshield wiper cowl and cleaned out leaves, etc., before turning the hose on to check the drain. Let the water run for quite a while and a small trickle started to show up coming down the seam in front of where the kick panel meets the firewall - it took a while for this to show up so I'm thinking there is a small crack somewhere, possibly behind the blower motor housing?
I purposely did not put any water on the windshield trying to isolate the source as best I could so I'm reasonably sure the leak is from the drain path and not the windshield. After watching a couple of Youtube videos on removing the blower motor, I proceeded to remove the glove box to get access to the wires and the top screws (7 mm) holding the motor in place - surprise! - the "behind the dash" picture of a 1994 Yukon is not the same as a 1996 K1500 - the ABS plastic A/C vent, two large wire looms, metal box that contains the (body computer?) that looks like a radio, and very tight space to get my large hands into is creating a problem.
Anybody out there with a similar vehicle that can provide some guidance on blower motor cover removal (appears to be two inaccessible screws for removal) and any special tools needed to get the motor out?
I've ordered some new carpet so I need to solve this problem - any and all thoughts, comments, suggestions are welcome.
 
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SgtPreston

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My 1994 Yukon SLE 4x4 (just purchased) went through the car wash to check for leaks - seemed to be tight around windows, doors, etc. so I was a happy camper - until I took the floor mat out to clean and found the carpet wet on the passenger side. Pulled everything out and noticed the carpet slightly discolored so it has leaked in the past, but fortunately no rust. After reading all the posts here I started on the checklist of possible leak sources and eliminated the heater coil as I had just replaced it, besides the leak is just water (no antifreeze), removed the windshield wiper cowl and cleaned out leaves, etc., before turning the hose on to check the drain. Let the water run for quite a while and a small trickle started to show up coming down the seam in front of where the kick panel meets the firewall - it took a while for this to show up so I'm thinking there is a small crack somewhere, possibly behind the blower motor housing?
I purposely did not put any water on the windshield trying to isolate the source as best I could so I'm reasonably sure the leak is from the drain path and not the windshield. After watching a couple of Youtube videos on removing the blower motor, I proceeded to remove the glove box to get access to the wires and the top screws (7 mm) holding the motor in place - surprise! - the "behind the dash" picture of a 1994 Yukon is not the same as a 1996 K1500 - the ABS plastic A/C vent, two large wire looms, metal box that contains the (body computer?) that looks like a radio, and very tight space to get my large hands into is creating a problem.
Anybody out there with a similar vehicle that can provide some guidance on blower motor cover removal (appears to be two inaccessible screws for removal) and any special tools needed to get the motor out?
I've ordered some new carpet so I need to solve this problem - any and all thoughts, comments, suggestions are welcome.

Okay, step two - I found a video of a '92 K1500 that was similar to mine so I was able to get the PCM, blower motor cover and blower motor out. Unfortunately after doing all that work, there is nothing obvious. Putting water in the cowl area doesn't show any leakage into the fresh air ducting to the blower motor but I can get some water (trickle) if water is sent down the door hinge area so I wonder if the hinge bolts go through to the interior. Still trying to find an obvious path for the water but nothing yet.
 

wjburken

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Folks here have discussed having the hinge break away from the pillar. Since these are welded in on your vehicle I believe, might look there.

One guy poured different colored water in different areas to see what color came through to help pin point the source.
 

warndogg

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Okay, step two - I found a video of a '92 K1500 that was similar to mine so I was able to get the PCM, blower motor cover and blower motor out. Unfortunately after doing all that work, there is nothing obvious. Putting water in the cowl area doesn't show any leakage into the fresh air ducting to the blower motor but I can get some water (trickle) if water is sent down the door hinge area so I wonder if the hinge bolts go through to the interior. Still trying to find an obvious path for the water but nothing yet.
Might sound silly but check the boot for the wire loom between the door and body. Water could get into your kick panel there and then leak onto the floor.
 
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SgtPreston

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Folks here have discussed having the hinge break away from the pillar. Since these are welded in on your vehicle I believe, might look there.

One guy poured different colored water in different areas to see what color came through to help pin point the source.

Thanks for the info Wade, I hadn't heard about the hinge pulling away from the pillar so it's something else to check. Good idea on the different colored water too, it just doesn't seem to have an obvious point of entry so maybe that will help. Appreciate the reply and I'll update the post if I solve the mystery.
 
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SgtPreston

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Might sound silly but check the boot for the wire loom between the door and body. Water could get into your kick panel there and then leak onto the floor.

Thanks Justin, but it doesn't appear to be coming in from the kick panel - when I've gotten enough water to make it leak, it seems to be coming down the front seam between the firewall and the kick panel. I'm beginning to suspect a body seam leak/fender/hinge but I can't get to a point where I can get some sealant to stop it. I'm concerned about applying sealant without a specific spot I can see - might plug something and just divert the water to a worse location.
 
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SgtPreston

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Okay, the saga continues - pulled the heater blower motor and could find no obvious path for the leak so went back to the cowl and put water on the windshield (pass side) and started to see water after a period of time.
Appeared to be a W/S leak, and it was in need of replacement, so in with a new W/S today and drove back to the shop to check out the result - still leaking #@#$&! I'm running out of "obvious" places to seal and I'm about to start some serious investigating, possibly pull the hood hinges and/or removing the pass. fender.
Short of sealing off the cowl area completely and starving the fresh air vent, any one have any other ideas?
 

warndogg

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Okay, the saga continues - pulled the heater blower motor and could find no obvious path for the leak so went back to the cowl and put water on the windshield (pass side) and started to see water after a period of time.
Appeared to be a W/S leak, and it was in need of replacement, so in with a new W/S today and drove back to the shop to check out the result - still leaking #@#$&! I'm running out of "obvious" places to seal and I'm about to start some serious investigating, possibly pull the hood hinges and/or removing the pass. fender.
Short of sealing off the cowl area completely and starving the fresh air vent, any one have any other ideas?

I hear ya! It can drive you crazy. Have you peeled back the carpet and trim to see exactly where it's coming in on the inside maybe get in the cab and have helper spray water?
 

east302

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Here is where I’ve always seen leaks, but it’s on three 98 models. It’s likely the same as a 94, so maybe it will help.

Pulling the carpet back and watching from inside while someone runs a hose is helpful.

1. Radio antenna grommet loose, though that’s usually the result of the dash being pulled. It’s under the blower.

ff80ba852b6f12a85776db2a6f4e2e72.jpg

2. Cowl plastic screw needs to be sealed (circled) or the seam sealer (X) is cracked.

The screw goes into the blower intake. Pull the blower and use a mirror to look up to the cowl. Put water on the cowl and see if water is coming in. That, however, fills the blower housing with water and usually kills the blower eventually.

The seam sealer cracking is pretty common. I’ve just sealed cracks with whatever goop I had handy, RTV or sometimes weatherstripping adhesive.

5a16982a61885ae885141d23a50c08dc.jpg

Last, is water accumulating in the sill plate at the door? Pull the plate to check.

A weatherstripping leak at the door can channel water down into the sill where it can overflow into the floor and/or the carpet edge can soak it up. On my 98 Tahoe (two door) the water was coming in from the vent in the inner door panel and some of the door panel clip holes, leaking down into the sill.
 
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SgtPreston

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Justin/East302, many thanks for the support - just to recap, I've replaced the W/S, pulled the blower motor, pulled the kick panel and sill plate, pulled carpet back and had someone hose the area above the pass. corner of the cowl area. No water around the antenna or door weather stripping but water seems to find it's way to the seam coming down from the upper intersect of the firewall and the inner fender. East302, you may have given me a clue about the seam sealer - it looks like it is sealed but the way it is "brushed" on the surface there could be cracks that don't show up to the naked eye. I think I'll spray that area with 'Flex Seal' sealant and add some silicone around the cowl screws. Appreciate the pics, those helped to see your seam sealer looks the same as mine. I'll let you know if this works.
 

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