Water Leak Passenger Side, Blower Motor Fried, Cabin Air Filter Wet

[Shahrkster]

Hey guys,
I have scoured many a forums and finally decided to post about this here since I couldn't get any good solutions or root causes.

I have a 2015 GMC Yukon SLT with about 199,800 miles on it. Bought it from a buddy and generally its is decent and I like it. The other day, I remote started the car, got into it and turned on the heat but the blower wouldn't come on. So after some research I decided to open up the panels under the vehicle to get to the blower motor thinking it was the common resistor issue. Anyway....when removing the floor coverings I noticed the follow:

1. The weathertech floor mats I have were not wet.
2. The factor carpet was wet close to the passenger door base.
3. When I pull this off, I noticed that the sound proofing/insulation (black) was also wet
4. When I removed the panels, it seems that water had been running down the A pillar because the wiring tape and such there were wet.
5. When I removed the cabin air filter (which was way overdue) it was damp as well. HUH!!

So I wonder if water got to the cabin air filter and leaked below to the motor (right under it and where the fan fins being cut out allow water into the motor- brilliant design GM!!!).

The question is where is this water coming from?
1. I have read about the shark fin leak issues but that seems OK. No water on the roof panel.
2. I have a sun roof that I rarely open but again roof panel is dry.
3. I dont run the AC at all (I turn it off if the climate system turns it on) since it is cold here. So I am pretty confident that it might not be the AC.
4. The vehicle was parked outside and I dont recall a lot of rain at least in the prior 7 days. I know this because I have been watching it to fix my yard (seeding, etc.)

So what gives?
What would be the root cause?
What would you do to diagnose this leakage?

When it comes to the blower motor, its receiving the 12V but it isnt running and the fuse is fine so its fried.

 

[STORMIN08]

any coolant smell to the liquid ?

could be a leaking heater core, could be windshield...those areas hold water for a long while once they get wet.

 

[Shahrkster]

No coolant smell. Just water. I will check again.

 

[STORMIN08]

go soak the vehicle with a hose (literally tie the hose up to the roof area) and dig around inside, then do an engine on test for similar issues

 

[Shahrkster]

OK. So here is some more detail. I changed the cabin air filter yesterday (let's call this day 1) evening. Brand new, dry to the bone out of the package (of course). Since I changed the filter, we had rainfall last night and this morning (morning of day 2 about 16 hours later) It wasn't hard rain but it wasn't a drizzle either. Since I changed the filter I have not driven the vehicle one inch.

After I posted the original note, I thought I would check the cabin air filter to see if it is wet. Low and behold, it was wet in a portion of it. See picture. Inserted into the filter assembly, the wet portion would be to the left side of the filter and this coincides with the air intake (I believe) for the cabin.

Any thoughts or guidance on if there are already solutions out there to fix this? Or do I need to go through the whole 9 yards of testing with water?

 

[JimHanus]

Here's my experience (I'm sure you'll hear more) which I never could fix. I had a similar problem, passenger floor under the carpet was always wet. Carpet is like a plastic material so it never soaked through (plus Weathertech mats). I literally spent days trying to find where the water was coming from (not coolant). Tried every suggestion I could find on line. Spent hours hosing down everything, taped over the seams, blocked cracks with putty, covered openings, ran water down drain lines. Used a scope camera that I could poke into every orifice looking for water. The water (what small amount there was) was running down the metal next to the dashboard, dripping onto the firewall (which is sloped) where it meets the side metal and down to the floorboard where it would puddle in a low spot until there was enough to spread around under the carpet. It wouldn't touch anything like carpet except where it ran down the metal. I gave up, and what I did was drill a hole in the floorboard and dish it out by hitting the floor with a ball peen hammer. I also made a little dam with silicone in case a lot got in there. The carpet is held up slightly by the adhesive that was used to stick it down so there is a space between carpet and metal. No more wet carpet.

 

[Shahrkster]

Here's my experience (I'm sure you'll hear more) which I never could fix. I had a similar problem, passenger floor under the carpet was always wet. Carpet is like a plastic material so it never soaked through (plus Weathertech mats). I literally spent days trying to find where the water was coming from (not coolant). Tried every suggestion I could find on line. Spent hours hosing down everything, taped over the seams, blocked cracks with putty, covered openings, ran water down drain lines. Used a scope camera that I could poke into every orifice looking for water. The water (what small amount there was) was running down the metal next to the dashboard, dripping onto the firewall (which is sloped) where it meets the side metal and down to the floorboard where it would puddle in a low spot until there was enough to spread around under the carpet. It wouldn't touch anything like carpet except where it ran down the metal. I gave up, and what I did was drill a hole in the floorboard and dish it out by hitting the floor with a ball peen hammer. I also made a little dam with silicone in case a lot got in there. The carpet is held up slightly by the adhesive that was used to stick it down so there is a space between carpet and metal. No more wet carpet.

View attachment 277728

Thanks for taking the time to reply. I see you have addressed the symptom and this seems like a nice last resort. Did you have a wet filter?

 

[JimHanus]

Thanks for taking the time to reply. I see you have addressed the symptom and this seems like a nice last resort. Did you have a wet filter?

No, only wet carpet. Yes it was a last resort. It's been 6 months and no wet carpet so I'm happy with it.

 

[Bill 1960]

I had a similar experience with a different vehicle and it was the sealant around the windshield. Had the windshield removed and replaced.

 

[Monkeywrench78382]

Hey guys,
I have scoured many a forums and finally decided to post about this here since I couldn't get any good solutions or root causes.

I have a 2015 GMC Yukon SLT with about 199,800 miles on it. Bought it from a buddy and generally its is decent and I like it. The other day, I remote started the car, got into it and turned on the heat but the blower wouldn't come on. So after some research I decided to open up the panels under the vehicle to get to the blower motor thinking it was the common resistor issue. Anyway....when removing the floor coverings I noticed the follow:

1. The weathertech floor mats I have were not wet.
2. The factor carpet was wet close to the passenger door base.
3. When I pull this off, I noticed that the sound proofing/insulation (black) was also wet
4. When I removed the panels, it seems that water had been running down the A pillar because the wiring tape and such there were wet.
5. When I removed the cabin air filter (which was way overdue) it was damp as well. HUH!!

So I wonder if water got to the cabin air filter and leaked below to the motor (right under it and where the fan fins being cut out allow water into the motor- brilliant design GM!!!).

The question is where is this water coming from?
1. I have read about the shark fin leak issues but that seems OK. No water on the roof panel.
2. I have a sun roof that I rarely open but again roof panel is dry.
3. I dont run the AC at all (I turn it off if the climate system turns it on) since it is cold here. So I am pretty confident that it might not be the AC.
4. The vehicle was parked outside and I dont recall a lot of rain at least in the prior 7 days. I know this because I have been watching it to fix my yard (seeding, etc.)

So what gives?
What would be the root cause?
What would you do to diagnose this leakage?

When it comes to the blower motor, its receiving the 12V but it isnt running and the fuse is fine so its fried.

If you live in a salt climate, the drain ports rust out and the drain lines leak as the right front corner drain runs over to the a pillar and down past heater box, the headliner in your model is Styrofoam backing water would not ********* to face side. Has the windshield been replaced in this truck? Improper installation could possibly allow water in and drip down on to heater box top where it can leak into the heater core cover which sits back under windshield tray. Solution open sun roof take a quart pitcher and fill tray and see if water comes out just behind passenger and drivers tires drains do plug up w dirt and debris compressed air into drains will clear them.

 

[Shahrkster]

Hey guys...I have been busy and so didnt really get a chance to follow up or work on this problem. Yesterday I did a few things. I removed the cowl, the air filter and the blower motor to see if I can diagnose this issue.
1. Checked for the plate (under the cowl and above the air intake) for leakage. The seals looked good on them. I also poured water to see if anything came through. Nothing.
2. I poured water all along the base of the windshield. No leakage into the air filter.
3. i poured water along all edges of the windshield. No leakages.
4. I poured water along the edges of the shark fin antenna. Nothing.
5. I checked for stoppages in the drain plug using a wire. No issues there
6. I ran the air conditioner for a bit to see if there was condensate. Again nothing.

In all cases 1-4, the water came down a channel behind the wheel well.

It rained a little through the evening and night and I checked the car for water leakage and there it was. So I am baffled as to what might be causing this. Any more ideas?

 

[Prospect62]

Hey guys...I have been busy and so didnt really get a chance to follow up or work on this problem. Yesterday I did a few things. I removed the cowl, the air filter and the blower motor to see if I can diagnose this issue.
1. Checked for the plate (under the cowl and above the air intake) for leakage. The seals looked good on them. I also poured water to see if anything came through. Nothing.
2. I poured water all along the base of the windshield. No leakage into the air filter.
3. i poured water along all edges of the windshield. No leakages.
4. I poured water along the edges of the shark fin antenna. Nothing.
5. I checked for stoppages in the drain plug using a wire. No issues there
6. I ran the air conditioner for a bit to see if there was condensate. Again nothing.

In all cases 1-4, the water came down a channel behind the wheel well.

It rained a little through the evening and night and I checked the car for water leakage and there it was. So I am baffled as to what might be causing this. Any more ideas?

Did you ever find the cause of the leak?

 

[Shahrkster]

If you live in a salt climate, the drain ports rust out and the drain lines leak as the right front corner drain runs over to the a pillar and down past heater box, the headliner in your model is Styrofoam backing water would not ********* to face side. Has the windshield been replaced in this truck? Improper installation could possibly allow water in and drip down on to heater box top where it can leak into the heater core cover which sits back under windshield tray. Solution open sun roof take a quart pitcher and fill tray and see if water comes out just behind passenger and drivers tires drains do plug up w dirt and debris compressed air into drains will clear them.

The windshield has been replaced from what I understand. Not sure how much it costs to get that done but might have to look into it. That said, I did pour water all around the windshield and the sun roof (while the sun roof was closed) and nothing came through on the inside. The water did pour out behind the wheels as you describe. I also cleaned out the drain behind the engine. So who knows what this problem might be. It is frustrating since GMCs of several generations seem to be having this issue and GM doesn't seem to care about it. I have seen 2022 vehicles with this problem. Oh well.

 

[Shahrkster]

Did you ever find the cause of the leak?

Nope.

 

[Shahrkster]

Hey guys - Wanted to give an update on this real quick. Two things have happened since I last looked into this.

1. There is a water drain behind the right/passenger side wheel well - Not sure if this is by design or it happened over time - I believe that it is there by design (please correct me if I am wrong). I was doing some rust rework and paint and noticed there was a lot of crud that had gathered in there and so I believe the water was not getting out as soon as it should. However, I DO NOT believe that this is the issue because I saw water leaking in the passenger side irrespective. It is something that people should check into.

2. I redid the water leak test and this time with a lot of water in different areas. Water started leaking after it was pointed at the sun roof. I thought I had cleaned the sunroof drains prior but maybe not enough. Once poked, the drain seems to be allowing the water to pass through the right channels rather than into the passenger side.

Suggestions - ensure water is draining from all drain paths - behind wheel wells and the fire wall. Then pour copious amounts of water to check each spot - cowl, then around windshield, then around sunroof, then around antenna, etc and do so patiently. If water is not draining out at the rate it is going in, it might be welling up before it leaks.

I hope I have found my leak source (sun roof drains) and will keep everyone posted.

 

[Shahrkster]

Well folks…I may have celebrated a little early. I did not however mark the task as “completed” on my reminders since I wanted to ensure this was fixed. I believe this is a two fold issues and I may have fixed just one of them. The other day it rained here and sadly the carpet was wet again. This time, however, I did not see any water dropping from below the A-pillar area. It was likely a blind leak that is occurring from behind the mat under the dashboard. For those not familiar with this, there is the floor board mat and then a mat that is at an angle under the dashboard. This mat has a plating/non-porous layer. Water seems to be getting under that somehow and going straight to the padding under the floor board. If anyone has any thoughts on how this may be happening, I am all ears. This leak is a b(&*^ch to figure out. Will keep the group updated.