Water leaks under the dash

Collimare · May 16, 2015

Update: My 2015 2500HD Duramax LTZ Crew Short (last 8 of the VIN: FF558385) was in the shop for a week. They finally isolated the issue to water penetration at the top of the passenger side windshield pillar. They removed the windshield and repaired/resealed the seam at the top corner, put the windshield back in. They retested and stated that it was the problem and is now dry. We will find out as I am headed from Denver to Chicago on Sunday and there is going to be plenty of rain. Not sure how it left the factory leaking so bad but maybe they really don't test them.

GMCustomerService · May 18, 2015

Hi Collimare,

We're very sorry to hear you were experiencing water penetration in your new 2015 2500 Duramax. It's good the dealer was able to address this for you. If you need any further assistance or have any questions, please don't hesitate to send us a PM. We're here if you need us and will be on the lookout for updates.

Sincerely,

Eddie A.

GM Customer Care

GuyGene · May 19, 2015

Grommet/gasket/seal to firewall has been where I've found leaks, except one windshield...

Collimare · May 21, 2015

Hi Collimare,

We're very sorry to hear you were experiencing water penetration in your new 2015 2500 Duramax. It's good the dealer was able to address this for you. If you need any further assistance or have any questions, please don't hesitate to send us a PM. We're here if you need us and will be on the lookout for updates.

Sincerely,

Eddie A.

GM Customer Care

It took a week and part of the problem lied in the fact that the Dealer was hesitant to remove the windshield because it was going to take 3 weeks to get a new one if it broke getting it out. So I insisted that they do their best to get it out with out breaking it and they did. It is very disappointing to spend this kind of money on a high margin product to have a very obvious quality defect. This is my third GM product in a row and it will give me hesitation in the future. Thank you for following up!

GMCustomerService · May 22, 2015

Collimare,

We appreciate the detailed update. We're glad to hear the dealership was able to resolve this for you despite the initial hesitation with removing the windshield. Your continued loyalty is important to us as we hope to continue being your prime vehicle choice. Feel free to reach out anytime if you have questions. We're only a PM away!

Sincerely,

Eddie A.

GM Customer Care

pm26 · May 24, 2015

It took a week and part of the problem lied in the fact that the Dealer was hesitant to remove the windshield because it was going to take 3 weeks to get a new one if it broke getting it out. So I insisted that they do their best to get it out with out breaking it and they did. It is very disappointing to spend this kind of money on a high margin product to have a very obvious quality defect. This is my third GM product in a row and it will give me hesitation in the future. Thank you for following up!

It almost seems that the price and quality at GM are inversely proportional nowadays.

rrctx · November 6, 2015

My 2014 Silv/duramax is doing the same thing. with the big rains in Texas it has now become more than a minor problem.

I recommend removing the door/floor trim piece and wedging something under the insulation to help it dry. I positioned a fan on it on a sunny day and it seemed dry. pain in the butt for a $60K truck

hairybumcrack · November 7, 2015

It almost seems that the price and quality at GM are inversely proportional nowadays.

That applies everywhere. In this day and age, companies are less concerned with workmanship and pride and will take risks knowing full well that they may have some fallout that they would have to payout from time to time. All of this is considered in business decisions. Inferior products from overseas are to blame for this shift in mentality unfortunately.

Not defending GM as I too am pissed at the issues I'm having with my 2014. Mind you, I've owned so many vehicles I'd still say that Dodge and Ford rank # 1 and # 2 as the biggest POS's out there. I had a 2006 Dodge 3500 with the famed 5.9L Cummins - the truck was a POS as I had to replace the entire front end within 40K miles and the engine developed severe blowback by the time it got to 70K miles. Funny thing is that I rarely towed with it and the heaviest item I towed was my 7000lb boat which was towed twice a year.

Rams01 · December 4, 2015

Just now found water sitting under the passenger side carpet after tracking down WTH my truck smelled like trash or something of that nature. No idea where it's leaking water from but searched the forums and it gave me a few places to look. I'm thinking it may be coming from the firewall given the extent of the moisture.

Just had 8in of rain fall in 72 hours here in Dallas, but didn't ever go through any high standing water. So now the question is.. Why the heck is my 2015 Z71 leaking water after 6 months of ownership. Sigh* It'll never smell the same again, I'm incredibly disappointed in that more so than anything. Oh, and the dealer can't get me in for another week to look at it due to them not having another loaner truck (need it for work).

Is this what I get for buying new vehicles? I had issues with my 2014 DC and as it sat in the shop for 5 weeks tracking down the issue i said screw it and traded it in for my 2015 thinking things would be better this time. I'm a GM fan, but it's becoming harder and harder to justify buying another new $42k+ Silverado come 2016.

pm26 · December 7, 2015

Yes you will get mold. My 2007 had this problem. It took a few years to rear its ugly head. MOLD IS VERY DANGEROUS!!. I am very sensitive due to having Asthma. Kept getting cold symptoms. Never smelled anything for about two years. The dealer had to strip everything out. Then I traded it in. Im just saying do not take it lightly. Good luck.

Yes, mold can be very dangerous to your health. Recently I saw a case on Forensic Files where people living in a large house that leaked undetected behind the walls got seriously ill from toxic mold and almost died. Hopefully nothing this toxic would grow in your vehicle, but the air volume is small and you should get the leaks fixed ASAP and thoroughly dry all affected areas.

Bigmac · December 13, 2015

Same leak on the e brake pedal and floor below it. I live in NW where it's raining daily. I took and ran a small bead of clear silicone around the roof antennae on one of the dry days and no more leak. Early 15 model. Just thought I would mention it.

pm26 · December 13, 2015

Same leak on the e brake pedal and floor below it. I live in NW where it's raining daily. I took and ran a small bead of clear silicone around the roof antennae on one of the dry days and no more leak. Early 15 model. Just thought I would mention it.

Glad you fixed it. That antenna gasket is probably too hard and not sealing properly.

batman900 · December 13, 2015

So do 90% of these issues stem from that darn antenna? Think Ima throw some silicone on it just for good measure.

SheeB · December 13, 2015

Hopefully GM redesigns this gasket so when mine finally fails I'll only need to have it replaced the one time.

Paden · March 13, 2016

In January, I purchased a used "certified" 2011 Silverado 1500 regular cab work truck with 66,000 miles on it from a GM dealer. It has a vinyl flooring. I noticed at the time of purchase that the door weatherstripping at the sill plate was cracked, and stained with rust. I didn't think this was an indication of any water infiltration issues. About a month later I took the truck through a car wash. A couple of days later, I entered the cab and felt ice crystals "crunching" under the flooring. I discovered that the padding under the vinyl flooring was completely saturated and had frozen on both the driver and passenger side floorboard. Water had apparently wicked up under the seats, though the padding was not as wet the further toward the rear. I removed the door sill plates to access the padding and begin drying out the padding. The amount of rust and obvious water marks along the plastic receivers that hold the sill plates in place indicates that the water infiltration has been a problem for a while. This is particularly troubling because wiring runs through these receivers. Fortunately, there does not appear to be any significant rust on the floor pan itself. With the vinyl mats pulled back as far as possible (without removing the seats, I dried the padding over the course of a couple of days. I called the local GM dealer (not the one I bought the truck from) and asked what I should do and whether this may be covered by the remaining warranty on the truck. The service department manager told me that it was doubtful if the problem would be covered by GM and that I should first take a look at the seal on the third brake light over the rear of the cab and see if the gasket was "wavy" and improperly seated. An improperly seated third brake light gasket was, she explained, the most common cause of water infiltration they see at their dealership. She also indicated that water leaks are hard to diagnose and that they typically charge about an hour's labor to test a vehicle in their wash-bay, which seemed reasonable enough. On further conversation and after reading some forums, I removed the third brake light assembly and found it to be slightly bowed. It also appeared from that the and that the gasket may not have been fully compressed whereas there were two spots on it that appeared brown with dust and pollen where water may have been able to pass through, perhaps under the pressure of a car wash. So, right or wrong, I applied a generous double-bead of a good exterior grade 3M silicone sealant to the gasket and re-installed the third brake light assembly. Then, after a day or two to let the sealant set up, and with the flooring and vinyl pulled back for inspection, I had a friend run a water hose continuously on the front of the truck starting low on the front fender at the door hinge area and very very slowly "climb" to the level of the cowling at the base of the windshield while I checked for water. We repeated the process on both sides. This did not produce a leak. Then I had him move up on the windshield in the same manner to no effect. Finally we moved to the third brake light. After applying a significant amount of water to all of these areas, there were still no leaks. The padding, sill area, and firewall remained totally dry. No leaks or water observed. I thought the problem was resolved with the application of sealant to the third brake light gasket.

The following week a very heavy but brief rain occurred. the truck was parked on a level driveway. I did not use the truck until a couple of days later. I opened the driver side door and found that the plastic receiver tracks to be very wet, though the padding was not. As I was moving around to the opposite side of the truck, I shut the driver side door. When I shut the door, water came pouring out from the underside of the driver's- side fender near the door hinge. When I looked under the truck in this area, I saw water exiting between what I think is the firewall and the fender. I suspect water is pooling somewhere in between the two. I saw in a forum where water can collect in the opening in the sidewall next to the emergency brake, wiring harness is mounted here behind the vinyl flooring. This may indicate a seam that is improperly sealed in the firewall door framing. I intend to contact the dealer tomorrow and discuss it with them. It would appear that the fender needs to be removed and the seams investigated and repaired.

Hi Collimare,

We're very sorry to hear you were experiencing water penetration in your new 2015 2500 Duramax. It's good the dealer was able to address this for you. If you need any further assistance or have any questions, please don't hesitate to send us a PM. We're here if you need us and will be on the lookout for updates.

Sincerely,

Eddie A.

GM Customer Care