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Posted

If I were to look at a new 20 or 21, would it make sense to spray water at the sliding rear window on the dealers lot to see if it leaks?

 

Should you focus on the upper passenger side or everywhere? Or is this something that always takes a while to show up?

Can't believe this hasn't been fixed by GM.

Any comments welcome.

Posted

Some leak right away, some take thousands of miles. No one ever posts their circumstances though like rough roads, cold nights and hot days, nothing to help us figure out what these leakers are going through. So there’s no foolproof way to determine if (maybe even not if but when) yours will leak.


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Posted

All of these sliders will eventually leak. Even if you never leave the pavement for thousands of miles, the slider will crack and it will leak at some point. You may get a few weeks, months, or possibly years, but it is a ticking clock. 

Posted
19 hours ago, steve8 said:

If I were to look at a new 20 or 21, would it make sense to spray water at the sliding rear window on the dealers lot to see if it leaks?

 

Should you focus on the upper passenger side or everywhere? Or is this something that always takes a while to show up?

Can't believe this hasn't been fixed by GM.

Any comments welcome.

Yes I would definitely!  It doesn't take much if it's leaking from day one.  I never took my truck off road and the weather has been mild, no freezing thawing cycles since picking up the truck and no popping sound as some have reported.  The dealer usually washes the truck prior to the sale.  There will be dried water spots on the inside of the window usually on the passenger or driver side of the window or actual water if it's been raining.  

Posted
26 minutes ago, Grey3liter4x4 said:

Yes I would definitely!  It doesn't take much if it's leaking from day one.  I never took my truck off road and the weather has been mild, no freezing thawing cycles since picking up the truck and no popping sound as some have reported.  The dealer usually washes the truck prior to the sale.  There will be dried water spots on the inside of the window usually on the passenger or driver side of the window or actual water if it's been raining.  

This is about the only advice that I - an owner of a leaker - would give you as a buyer... have the dealer run it through the wash while you're there, then inspect the rear window for any drips or look for any dried stains if the truck has been parked outside for a while and it has precipitated. You'll see the water marks there if it's been leaking. 

 

8/10, however, don't likely leak right away. Maybe 9/10. So don't count on finding a leak when you're buying. If you do, great. But... having the dealer get you a different truck does not change your chances of getting a leaker at all.

 

If you get a truck with a sliding rear window, it WILL leak. Many of us went 5K-7K miles before the leak started. Others, much sooner. GM has not materially addressed this, so the leaks will continue on at least until the 2022 refresh hits. 

Posted
1 hour ago, Grey3liter4x4 said:

Found this online on a general search.  Most of you may already know about the TSB link but here it is https://static.oemdtc.com/TSB/MC-10156903-9999.pdf.  Going to print this out and bring it in with me to the dealer.

That’s an older copy. The newer TSB goes through all 2020 models.

 

https://static.nhtsa.gov/odi/tsbs/2020/MC-10171889-9999.pdf

Posted

For the people who had theirs leak did you actually open the rear window and use it prior to leaking ?


Ryan B.

Posted

Thanks for the responses/appreciate it.

Beyond pathetic that this is an issue!!

Posted
3 hours ago, RyanbabZ71 said:

For the people who had theirs leak did you actually open the rear window and use it prior to leaking ?


Ryan B.

I used mine 2 times total. 

After I discovered the leaking issues, I quit using it hoping to delay what seems like the inevitable 

 

I actually really like having it, along with the front windows, open in nice weather but chose to keep it closed so it wouldn't leak....

Posted
5 hours ago, RyanbabZ71 said:

For the people who had theirs leak did you actually open the rear window and use it prior to leaking ?


Ryan B.

Yes. 
 

To me, there doesn’t seem to be a correlation. I used mine a lot before it started leaking. Then didn’t use it much after they “sealed it”, and it leaked again. Now I just use it whenever I want and have stopped thinking much about the leaking. 

Posted

Opening and closing the slider has nothing to do with the leak. The slider itself is not leaking, but the plastic frame that is sandwiched between the cab and the glass is cracking causing the leaks. The only way to not have a leaking rear glass is to buy a truck without the slider as the solid rear glass does not have the plastic frame. Mine was leaking when I bought it. It had be on the lot for about 6 months. Had 2 miles on it when I bought it. The plastic just gets cracks in it over time. Has nothing to do without how it is driven. Mine leaked on both sides. I agree that this should not be happening, but I still do not care for the other makes of full size trucks. My dealer/tech cured the problem the first time with the sealant, and have not had an issue since, and that was June of 2019. Some on here say that they still had a leak after it was sealed. I say that the dealer/tech is the issue with that. If you know how to lay a good bead of sealant it will cure the problem.

 

I will say I have been more disappointed with the issues I've had with this truck than any I have owned. It has had the rear glass leak, a bad battery, the tranny fluid issue, 6 recalls, and just last week had to have the evaporator replaced on the a/c because it was leaking. I have owned over 40 GM vehicles over the years, and have never had one to have this many issues ever, much less in the first year of ownership. Never had an evaporator to leak on any vehicle, but this one did. Still like the truck though, and will buy another one. Will wait and see what the 22' models are all about.

Posted

I have a 2020 Sierra. I have a sun roof and a rear slider

I live in near Syracuse, so we get quite a bit of temperature variation.

I generally wash my truck at home, but also wash it at coin operated places with  the high pressure wand and also high pressure touchless car washes.

I use the rear window all of the time -my dog loves to stick her head out of it and I like the sound of the performance exhaust.

It now has 4,500 miles and I have not had any leaking.

I must be lucky, but I had the same on my 2015 Sierra, that I traded in with 50,000 miles on it and not leaks on that one either.

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