Non-clogged sunroof leak troubleshooting

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Jonathan Case

Jonathan Case

Joined
Sep 11, 2016
Threads
19
Messages
85
Location
Silverton, OR
Website
www.jonathancase.net
Hi team —

So, my cruiser has started leaking at the sunroof on the passenger side, with water drops collecting on the right rear of the headliner rim, right below the sunroof rim (see pic, no water in the shot, but this is where it collects/drips). I snaked the front drains, tested with water for flow, and they seem clear. I also park on a slight nose-downhill orientation, so water is definitely not running back towards the rear - and yet it’s collecting near the rear of the sunroof. The sunroof seal seems to be in good shape, but I haven’t applied silicon to it since getting the rig this summer. That’s my next step, but wondering if anyone has other ideas. I dealt with a similar issue on my last 100 eventually by replacing the whole sunroof. :P Of course hoping to avoid that, but we shall see. No aftermarket roof rack or anything up there, so I don’t —think— water is coming in through another part of the roof.

IMG_1532.webp
 
The common leak point is the seal at the middle of the rear of the glass. You won't see it leak there unless you remove the trim, and then it'll drip right from the center. What's happening is that the water is following the trim and leaking out where the clip is. I have had this problem on the last reseal job I did. It took a while to find it.

If your seal is original, replace it. No amount of silicone is going to restore it. FWIW, silicone doesn't do anything for rubber, it only does something to it,by building up a silicone layer on it. Rubber is organic, silicone is not; they do not like each other.

The procedure is in the service manual. If you don't have one, get one from the Resources section.
 
Malleus said:
The common leak point is the seal at the middle of the rear of the glass. You won't see it leak there unless you remove the trim, and then it'll drip right from the center. What's happening is that the water is following the trim and leaking out where the clip is. I have had this problem on the last reseal job I did. It took a while to find it.

If your seal is original, replace it. No amount of silicone is going to restore it. FWIW, silicone doesn't do anything for rubber, it only does something to it,by building up a silicone layer on it. Rubber is organic, silicone is not; they do not like each other.

The procedure is in the service manual. If you don't have one, get one from the Resources section.
Click to expand...
Thanks for the response. In searching this up on Mud, I see some alluding to their leak point being the plastic and sunroof glass connection point, where water on top of the glass slides under the failing bond there, in which case replacing the gasket alone wouldn’t address the leak. Was your leak solved by just a new gasket?
 
Yes.
 
Following this. I have the identical issue.

Leaking sunroof surround - help troubleshoot? - https://forum.ih8mud.com/threads/leaking-sunroof-surround-help-troubleshoot.1361489/

Let’s distinguish between the sunroof rubber WEATHERSTRIP SEAL, which fits between the sunroof glass assembly and the roof sheet metal, and the plastic GLASS FRAME, which sits inboard of the weatherstrip seal.

A leaking rubber weatherstrip seal will send water into the gutter around the perimeter of the sunroof and down the drains (in a properly clean and functioning sunroof). Even with a bad seal, water should never enter the cabin.

The plastic glass frame has a small joint at the center rear of the sunroof glass. If water gets through the joint, or under the plastic glass frame in any other spot, it will drip into the cabin because the plastic glass frame sits inboard of the gutter. Technically, water seems to drip into the interior plastic sunroom garnish, where it can then flow and drip from another spot depending on how the vehicle is angled.

Last spring, water was dripping on my head in the driver position, but only on turns. I taped the whole rearward side of the glass frame, and it stopped. Now it’s back after a dry 4 months.

I have a new weatherstrip seal to install, but is suspect it will do nothing. Other posts here suggest that getting some sealant in between the glass and the glass frame is the solution.
 
Super77 said:
Following this. I have the identical issue.

Leaking sunroof surround - help troubleshoot? - https://forum.ih8mud.com/threads/leaking-sunroof-surround-help-troubleshoot.1361489/

Let’s distinguish between the sunroof rubber WEATHERSTRIP SEAL, which fits between the sunroof glass assembly and the roof sheet metal, and the plastic GLASS FRAME, which sits inboard of the weatherstrip seal.

A leaking rubber weatherstrip seal will send water into the gutter around the perimeter of the sunroof and down the drains (in a properly clean and functioning sunroof). Even with a bad seal, water should never enter the cabin.

The plastic glass frame has a small joint at the center rear of the sunroof glass. If water gets through the joint, or under the plastic glass frame in any other spot, it will drip into the cabin because the plastic glass frame sits inboard of the gutter. Technically, water seems to drip into the interior plastic sunroom garnish, where it can then flow and drip from another spot depending on how the vehicle is angled.

Last spring, water was dripping on my head in the driver position, but only on turns. I taped the whole rearward side of the glass frame, and it stopped. Now it’s back after a dry 4 months.

I have a new weatherstrip seal to install, but is suspect it will do nothing. Other posts here suggest that getting some sealant in between the glass and the glass frame is the solution.
Click to expand...
Thank you — yeah, I’ve read that a few people have used adhesives like RTV around the plastic glass frame. I’m going to try that using tape on either side of the seam to make a clean line.
 
Posted back to my thread on the topic here

Super77

Thread 'Leaking sunroof surround - not the weatherstripping seal or drains!'

I’ve got a drip coming from the sunroof glass assembly.
IMG_8129.jpeg


IMG_8130.jpeg


IMG_8132.jpeg

Left and right sides. Seems to be coming from the black plastic surround - Toyota calls it garnish - that’s visible from inside the vehicle (outlined in red above). The joints in that surround are wet, and the water pools and drips as shown in the photos. When the car has been sitting in the rain, the first time I hit the brakes, a trickle of water pours from that area.

I don’t believe this is a drains issue. The “moat” around the sunroof opening in the roof is clean, there is no water...

With a how-to.
 
Just a note to complete this: using a little black RTV on the seam of the plastic trim around the sunroof glass absolutely worked! I didn’t even get the sunroof perfectly realigned when screwing it back on, meaning some sunlight was visible passing through the outermost rubber seal down to the hinges and water channel, and even in that condition, water did not come down into the cabin because the leak point was addressed, and the sunroof drains continued to do their job.

The steps, roughly, for my 2002 cruiser:

1. Remove four black trim pieces (mine popped right off without breakage, but some care is warranted here).
2. Ratchet off four bolts holding sunroof in place on its mounts.
3. Remove and clean sunroof.
4. Apply a few dabs of RTV on the small seam of the plastic trim (down and around the small seam, gently pulling the rubber gasket aside for access). I cleaned excess up with a wet paper towel.
5. Reverse steps to put sunroof and trim back.

Whole process took less than 20 minutes, and so far so good on the repair!
 
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Yep, mine is holding as well. I applied even less and focused mostly on sealing up that tiny seam/crack in the rigid plastic glass surround.

The rubber weatherstrip gasket around the sunroof is really more about keeping out wind. A bit of water gets past it all the time and in a properly kept sunroof assembly, it gets channeled down the corner drains.
 
This could not have been better timing. Massive amount of water on my floorboard this morning and my head liner seems wet. This is something to look at. I do not mind problems. But I despise problems that I do not know where they are coming from. Thanks for some good direction.
 
You can test to see if this is actually your problem by placing a 4 inch long stip of painter's tape over the middle (side to side) of the rear metal/rubber on the sunroof. Don't worry about getting the glass, just place the tape over both the metal and rubber, at least 2 inches on either side of the seam, and overlap the roof skin. If that's the source of your leak, the tape will cure it. Temporarily.

You then need to find out which is leaking, the metal sunroof frame or the rubber seal. Cut the tape back to just the metal, and if it leaks, the rubber seal should be replaced. If it doesn't, you have a choice to make, since the leak is between the glass and the frame. The sunroof assembly is the glass, metal frame and other stuff, none of which is available separately. You can buy a new assembly, or squirt some seal magic in the gap and hope that stops the leak.
 
Malleus said:
You can test to see if this is actually your problem by placing a 4 inch long stip of painter's tape over the middle (side to side) of the rear metal/rubber on the sunroof. Don't worry about getting the glass, just place the tape over both the metal and rubber, at least 2 inches on either side of the seam, and overlap the roof skin. If that's the source of your leak, the tape will cure it. Temporarily.

You then need to find out which is leaking, the metal sunroof frame or the rubber seal. Cut the tape back to just the metal, and if it leaks, the rubber seal should be replaced. If it doesn't, you have a choice to make, since the leak is between the glass and the frame. The sunroof assembly is the glass, metal frame and other stuff, none of which is available separately. You can buy a new assembly, or squirt some seal magic in the gap and hope that stops the leak.
Click to expand...
Due respect, this is not accurate advice.

The rubber seal around the perimeter of the glass assembly is not designed to be watertight. It routinely lets a little water through, by design. Leave your sunroof tilted up in a light rain and you’ll see how: That water collects in the channel that surrounds the sunroof opening and drains through the 4 corner drains. If your rubber seal is not torn, brittle, or deformed, replace it last. It’s more likely that one of the drain channels is clogged, or (like in this thread) water is getting through the rigid plastic glass frame.
 
4 drains?! lol. Now that you say it, it makes total sense. However I only thought there were 2 in the front. So now I know what to focus on. In the mean time I covered the roof with plastic and painters tape. One more night of rain. Hope I didn’t hijack anyone here.

I was able to slide open the sunroof. This is what I found on the rear of the glass
IMG_6395.webp
IMG_6394.webp

The glass was also a little fogged. So this is a good place to start.
IMG_6393.webp
 
If it’s coming through the rigid plastic glass frame, water will drip into the garnish like into a gutter and then travel left or right inside the garnish and probably drip from the corner, where the rear and side garnish pieces meet.

But I’d look at the rearmost sunroof drains first. You can quickly test them just by lifting the front a little and pouring a cup of water into the drainage channel. Where does it go?
 
FWIW, I've spent decades designing experiments to test automotive component failures, and compiling PFMEAs and RCAs. My suggestions were designed to do exactly what is being suggested, in the order necessary to find the root cause of the leak:
1) test the rear sunroof drains, to ensure they flow freely, or at least freely enough to evacuate water ingressing;
2) test the rubber seal around the perimeter of the sunroof assembly to ensure it performs its design function, namely to exclude enough ingressing water to allow the drains to function properly;
3) test the frame–glass seal against water ingress.

I've used this method previously and I know it works.
 
Malleus said:
FWIW, I've spent decades designing experiments to test automotive component failures, and compiling PFMEAs and RCAs. My suggestions were designed to do exactly what is being suggested, in the order necessary to find the root cause of the leak:
1) test the rear sunroof drains, to ensure they flow freely, or at least freely enough to evacuate water ingressing;
2) test the rubber seal around the perimeter of the sunroof assembly to ensure it performs its design function, namely to exclude enough ingressing water to allow the drains to function properly;
3) test the frame–glass seal against water ingress.

I've used this method previously and I know it works.
Click to expand...
@Malleus I’d agree with your 1/2/3 order above since it starts with checking the 4 drains. As you say:

exclude enough ingressing water to allow the drains to function properly

So water getting past the rubber seal is not necessarily a problem, as long as the drains let it out. Reading through a few older sunroof threads here suggests some people don’t understand that leak ≠ bad rubber seal. I made the mistake of buying a new seal only to discover it had nothing to do with my leak. I think we’re both trying to say that the sunroof is a whole system, not just a big plugged hole.

I value your expertise here. ‘Mud is a better place when we can debate and learn.
 
I wasn't picking, I just wanted to state that there are many ways to get to the same end.
 
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