2008 Yukon 2500 Wet Floor

dieselman4224

New member
Jul 7, 2011
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NoVA
Hey all, I have a 3/4 ton Yukon that’s the family truckster. It has a consistently wet front passsenger floorboard. It does not smell like antifreeze. The coolant level has remained the same. I carefully snaked the A/C drain line and feel positive air pressure from the tube when system is on. We’ve had a lot of rain lately, with some snow and freezing rain. Any one have any thoughts?? TIA
 

SoCalMike

Member
Dec 12, 2010
758
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SoCal
Do you have a sun/moon roof? It could be coming from a failed seal/silicone between the windshield and frame of the truck
 

dieselman4224

New member
Jul 7, 2011
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NoVA
No sunroof.

I checked the door harness seal. Could I just pin a hose down at the top corner of the windshield and see if water is coming in? With the carpet padding rolling up the floorboard toward the heater it’s hard to tell if the water is coming down the firewall/top of floor pan OR if it’s coming from the A pillar somewhere.
 

dieselman4224

New member
Jul 7, 2011
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NoVA
Could I also pull the door seal and exterior windshield to pillar trim and get any idea if the windshield sealant has broken down?
 

SoCalMike

Member
Dec 12, 2010
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SoCal
Your going to have to pull that carpet back to see. Both of those ideas sound like a good place to start.
 

dieselman4224

New member
Jul 7, 2011
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NoVA
I’ve pulled the carpet and underpayment back to the floor pan. The horizontal pads are wet and the inclined portion of the floor padding is wet. That’s where I’m at a loss. I can’t tell if the water is coming down from the firewall/heater core or if it’s wicking up from the bottom flat area.
 

CarolinaHD

Member
Feb 8, 2011
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NC
Its probably clogged with leaves and dirt under the windshield cowl, filling up with water, and draining through the blower motor area.
 

dndj

Boost!
Apr 13, 2019
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Oregon
Dry everything out with a hair dryer. Crawl inside with a flashlight while a friend with a garden hose runs water over all suspect areas - cowl, front window seals, door seals.
 

testdrive

Member
May 28, 2013
64
1
8
Hey all, I have a 3/4 ton Yukon that’s the family truckster. It has a consistently wet front passsenger floorboard. It does not smell like antifreeze. The coolant level has remained the same. I carefully snaked the A/C drain line and feel positive air pressure from the tube when system is on. We’ve had a lot of rain lately, with some snow and freezing rain. Any one have any thoughts?? TIA
What model is your Yukon XL. If it is a 2001 or 2002 it has a cabin filter that is replaceable. What I suspect is that the leave and other debris is stacked up in the bottom of the evaporator box. There are two filters side by side, so take the plastic hush cover from underneath the right part of the dash and then remove the one screw that secures filter cover plate. Bet you'll be surprised at what comes out. Any parts store or walmart has the replacement filters.