rear vents leaking in Duramax

[TackDriver284]

Noticed wet carpets in my truck after some rains from time to time. Rain wasn't so heavy until last week and yesterday, had to remove front seats, rear seat, carpets and mats to air dry and after it was dry after 3 days, it rained again and I went out in the truck to check after rain stopped to see if i could find the leak, pulled the panel mats and there it is, its the rear cabin vent relief valve and they are missing all of the rubber flaps. Got some new GM parts and installed them this morning, now I need a little break, set up the fans again to air dry the truck. Hopefully soon I can get everything back in the truck again. If anyone has the Duramax HD2500 or GM SUV's and you have wet carpets, please do check the rear cab area for these vents. Side note, since i had the truck backed up in the driveway, and front area was wet as well, but common sense tells me that we have a slanted driveway and gravity, and instead of searching the front for the leak, I concentrated in the rear where the leak was, water traveled from the rear to the front.

 

[JD338]

Mark,
Thanks for the heads up. What year is your truck?
I have a 2018 GMC Sierra Duramax and haven't had any problems.

JD338

 

[TackDriver284]

Mark,
Thanks for the heads up. What year is your truck?
I have a 2018 GMC Sierra Duramax and haven't had any problems.

JD338

It's a 09 HD2500. I will stop at the auto store and get some black or blue silicone before I assemble the seats, I like to put a thin ribbon of silicone to cover the mating surface of the plastic and metal panel from the inside to ensure a proper seal for the years to come.

 

[RL338]

Good thing you caught it in time.
I had a ‘85 Ranger with a sliding rear window that I never knew it was leaking until my foot fell thru the floorboard. With a standard cab the seat was up against the cab , the water was soaked up the sound insulation and had a vinyl floor mat over the top. From the underside you would have never known it was rotting from the inside out.