Water stain

Deus13 · December 20, 2019

I have a 16 Sierra, Crew Cab with a sun roof and after a hard rain unnoticed the headliner against the back of the truck has a water stain on it. Does anyone know where it could be leaking from?

JimCost2014 · December 20, 2019

37 minutes ago, Deus13 said:

I have a 16 Sierra, Crew Cab with a sun roof and after a hard rain unnoticed the headliner against the back of the truck has a water stain on it. Does anyone know where it could be leaking from?

I would say, either your 3rd brake light, or you have clogged drains on the sunroof.

Is it wet anywhere around the sunroof itself?

Jmanson6262 · December 20, 2019

A dude I work with has a 16 silvy and said he had to take his in for this. They replaced the 3rd brake light and some modified gasket. Not sure if it was a TSB or what?

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Deus13 · December 21, 2019

10 hours ago, JimCost2014 said:

I would say, either your 3rd brake light, or you have clogged drains on the sunroof.

Is it wet anywhere around the sunroof itself?

I didn’t notice any moisture around the sun roof. The sun roof is loud while driving so maybe the seal is bad, I can hear some air movement while driving

JimCost2014 · December 21, 2019

21 minutes ago, Deus13 said:

I didn’t notice any moisture around the sun roof. The sun roof is loud while driving so maybe the seal is bad, I can hear some air movement while driving

Can you hear the noise when it is closed, or in the tilt position?

As bas as it sounds, no moisture around the sunroof is a good thing, which could have been a bad "Sharkfin" antenna, bad seal on the glass, windshield, and so on.

I would take a garden hose and soak the back of the truck (third brake light, rear window), just to see if it looks like it is getting wet.

If you can do the leg work for the dealer, you might be able to get it fixed quicker, because these leaks will not go away by themselves.

CamGTP · December 21, 2019

3rd brake light leak is what mine was. I removed mine, cleaned the surface up real good and put it back together with some sealant on the stock gasket. Haven't noticed it being wet again and I've gone through many storms and 50+ touchless car washes.

15slvrDbl · December 21, 2019

13 hours ago, Deus13 said:

I didn’t notice any moisture around the sun roof. The sun roof is loud while driving so maybe the seal is bad, I can hear some air movement while driving

You probably would not have. Most modern vehicles with factory sun roofs have drain tubes that run from the corners of the sunroof down to the pillars. If one drain is leaking it is possible to have water getting in in different areas.

Deus13 · December 22, 2019

On 12/20/2019 at 10:35 PM, CamGTP said:

3rd brake light leak is what mine was. I removed mine, cleaned the surface up real good and put it back together with some sealant on the stock gasket. Haven't noticed it being wet again and I've gone through many storms and 50+ touchless car washes.

What kind of sealant did you use? And will something like Oxyclean and a shop rag get the stain off the headliner?

Edited December 22, 2019 by Deus13

Willie's Ride · December 23, 2019

I have a 2015 Silverado High Country with a leaking sun roof. The dealer tested and said it was the 3rd tail light. Replaced with the GMOE light and a bead of silicone. The light does not leak. Next day a steady rain and the passenger side headliner is soaked again. A $55K vehicle should not leak. This is my 5th GM truck but the first with a sun roof. My retirement present to myself, but this leak is a pain. Both the dealer tech and myself checked the drains and no blockage. Next week back to a different chevy dealer and the GM Rep.

Any ideas on a fix?

Willie

citydriver · December 23, 2019

I have a '13 with a sunroof. after a couple of years my fastening hardware became slightly loose on the passenger side. I really didn't notice any leaks, however I did notice that the glass was not seating correctly on the seal. The glass was slightly higher than the roof. When I looked for an adjustment is when I noticed one of the screws had loosened. Once I tightened it after making sure the glass sat right, I haven't had a problem. but I do keep an eye on it. I also make sure to open it fully and clean the seal on a regular basis. I also lubricate the seal with silicone spray and a rag, not to mention making sure the drains are kept clear and in working order. There is also a Sunroof motor/actuator teach/relearn procedure that the dealer can perform after all adjustments have been verified.

Deus13 · December 23, 2019

On 12/20/2019 at 10:35 PM, CamGTP said:

3rd brake light leak is what mine was. I removed mine, cleaned the surface up real good and put it back together with some sealant on the stock gasket. Haven't noticed it being wet again and I've gone through many storms and 50+ touchless car washes.

I cleaned off the gasket, dries off the headliner, got all the moister out of the 3rd brake light and set a nice clean bead of bath tub silicone around the gasket. It’s still raining so if I wake up with a wet headliner then I guess it’s the sun roof drainage tubes

Deus13 · December 23, 2019

20 minutes ago, citydriver said:

I have a '13 with a sunroof. after a couple of years my fastening hardware became slightly loose on the passenger side. I really didn't notice any leaks, however I did notice that the glass was not seating correctly on the seal. The glass was slightly higher than the roof. When I looked for an adjustment is when I noticed one of the screws had loosened. Once I tightened it after making sure the glass sat right, I haven't had a problem. but I do keep an eye on it. I also make sure to open it fully and clean the seal on a regular basis. I also lubricate the seal with silicone spray and a rag, not to mention making sure the drains are kept clear and in working order. There is also a Sunroof motor/actuator teach/relearn procedure that the dealer can perform after all adjustments have been verified.

Where are these drains at? I’m sure they are close to the same spot on a 16 as a 13

JimCost2014 · December 23, 2019

On 12/21/2019 at 8:03 AM, 15slvrDbl said:

You probably would not have. Most modern vehicles with factory sun roofs have drain tubes that run from the corners of the sunroof down to the pillars. If one drain is leaking it is possible to have water getting in in different areas.

Correct, but if the Shark fin is leaking he would see the stains from the water, or like my 14 be able to feel the water by touching it.

JimCost2014 · December 23, 2019

2 minutes ago, Deus13 said:

Where are these drains at? I’m sure they are close to the same spot on a 16 as a 13

I would think so, two drain out by the front fenders, rear two drain out behind the doors at back of cab.

citydriver · December 23, 2019

6 minutes ago, Deus13 said:

Where are these drains at? I’m sure they are close to the same spot on a 16 as a 13

When you open the sunroof fully and look from above, you should see what looks like a plastic tray, stretching across the front. There are holes in the front corners aprox. 1/4 inch diameter. the rear drains are harder to see. but you can usually make them out using a flashlight. I usually take a bottle of water and slowly pour a little water in the trays and make sure the water is flowing out.