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Heater box seals leaking in rain water!

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Discussion starter · #21 ·
OpalLacod said:
Glad it's fixed! What a freak failure location...
Click to expand...
Yeh, my thoughts exactly. But then I realized .... not as "freak" as it would have been if it had turned out to be that 'seal/gasket' between the heater box and firewall. After discovering the leak the second time after bringing my truck home, I went over the old seal that had been replaced with a fine toothed comb and a magnifying glass. Nowhere on the seal, either side was there any indication of a water trace. I even took a few detailed pictures for future reference if needed. It was not much more than a piece of open cell foam rubber, and as I understand is pinched in between the inner side (cabin side) of the firewall and the face side of the heater/blower box. Open cell foam is never used for a water tight seal, only an air seal. In this case it prevents the higher pressure air from the blower from escaping between the box and firewall thereby forcing it out through the duct system, and also I guess prevents any foul air from the engine bay from entering the passenger cabin. But, that foam rubber seal is pinched in between those two flat surfaces which never move. No logical reason for it to ever fail unless it is so old as to be completely rotten, dried out and crumbly. I've been told there is some kind of TSB about that very seal failing, but I've not seen nor heard of it till now. Anyone out there heard of this seal ever being an issue? I may be picturing it all wrong, but I think I'm pretty close.
 
#22 ·
Guess I'm just sceptical, by nature; but those grommets are not designed to keep out water. It is my opinion that if water gets to it, it will leak.

So, from your description this point is behind the fender and part of the lower area of the A pillar; and, you check the truck after a heavy rain and the truck was parked during the rain.
My question, how did the water even get to the grommet?

I see it's only been a few hours from when you provided the update, and I expect the weather is nice.

I hope, when it rains, that I'm proven wrong.

Good luck Joe

And Joe, if it does leak, tape off the vents at the base of the windshield, use lots of duct tape, and see if that stops it.
 
Discussion starter · #23 ·
OK, here's where I think we are. 1st, it rained this morning and afterwards all was dry. It wasn't a real hard rain, but enough I think to have shown up if it were still leaking. Now, as to how the water gets to the grommet. The best I can tell is that all the water runoff from the windshield and the cowl vents is collected in a 'trough' at the base of the windshield and under the cowl vents, right at the very back edge of the hood. And BTW, there is a pretty substantial rubber seal under the very back edge of the hood and all the way across that prevents any of this water from entering the engine bay at the rear of the hood. That water is then channeled to either side of the truck and falls down through the opening behind the inner fender, and in between the outer fender and the truck body. If you'll visualize removing the fender, what you would see is the side of the body directly below the 'A' post and at he front of the door. Between the wheel opening at the front and the door opening at the rear. I've really looked and see no other option. I have to assume that this is fairly common for the run-off water in most vehicles, I've just never thought about it before. I'm definitely not a 'paint/body' man. But, what I don't understand is that down in that open space between the fender and the body, I can see some kind of insulation that resembles 'rock wool'. Likely some kind of sound deadener. No doubt this insulation is impervious to water, otherwise it would stay soaked and lead to a bad rust situation on the inside of the fender. As for the harness grommet not being water proof, I think the design is that the wiring harness is pulled downward at the outside of the grommet and through-hole so that any water getting on it will drain away from the truck rather than follow the harness into the truck. Since I didn't actually see the actual grommet and was only told by the tech it had cracked/split, leads me to believe that when it cracked it allowed the harness to follow it's natural direction while under bend tension and to rearrange itself to an upward direction just enough to allow the water to flow into the truck instead of away from it. It wouldn't take much of a change in how that wire bundle lays. That would would explain why it (the leak) started all of a sudden. It's a hell of a chunk of wire (about an inch+ in diameter) in that harness and a pretty small area to be bent to control the direction it lays. I'm totally amazed at the design of the water flow from the windshield and cowl vents being directed down through the opening between the fender and the truck body, but after thinking about it, I don't know where else it could be channeled. There's just enough room between the battery and the fender to look down through that opening to see where the water is supposed to flow, and with a good flashlight it can be seen. I'd appreciate anyone who has a similar truck to look at theirs and see if they agree with my description. I'll be checking back from time to time till midnight tonight ..... after that the cable company is taking down our I-net service for some kind of maintenance. Won't be back up till early hours of the morning, but I'll be back again after that.

thanks and regards,
jumpinjoe
 
#24 · (Edited)
jumpinjoe said:
OK guys, here's the "rest of the story". After a two week stay, they called and said it was all dry and ready to go. While picking it up I had opportunity to talk with the tech who had done the work. He swears he had done it right, including my instructions about putting it all back together right with no pinched air ducts, no electrical and/or electronics left disconnected, and that he had tested it with water spray and all was well. Well hell, I took it home and 3/4 days later we had a pretty serious rain again. I happened to be walking the dog that afternoon so decided to go past my truck and check the floor...... and guess what! The damned floor was wet. Same as before. I knew the dealership was closed but I called and left a voice mail msg telling them it was still leaking and how aggravated I was. I got a call from them Monday morning telling me to bring it back in as soon as I could. Well obviously I wanted to get it back in to get it fixed, so back it went that afternoon. Now let me emphasize here that I believe the tech thought he had pinpointed the leak, and I'm convinced he truly thought he had it fixed. At any rate, after a couple days, I got a call telling me they were having a really hard time pinpointing the leak and had to take off the front fenders, part of the grill, obviously the cowl vents, and other assorted parts. Today (this morning) after almost another 2 weeks, the service writer called and said it was done. So, off I went again to pick it up with a hollow in my stomach thinking it would never be the same again after taking that much of it apart. However, in all fairness it looks good. All the gaps are equal as they should be, nothing was beat up and all looked OK with one minor exception. Someone, probably at the body shop had left little smears of silicone or caulking, or heavy grease in a few places where they had obviously touched. Not a big deal after the relief of seeing it all back together again. I used some paper towels and most of it wiped off reasonably easy. The final problem turned out to be a failed wire harness grommet where it goes through the sidewall of the truck down inside the fender where the cowl vents drain. The water draining was apparently running down onto the wire harness and following the harness in through the body panel directly below the 'A' post, just a few inches below where the radio antenna lead enters the body. That harness turns right inside the truck body and follows along the right inside wall of the truck down to the floor and towards the rear. I'll say this .... it would have been literally impossible to discover this without removing the fender. And as fearful as I was that it would never all go back together right, they actually exceeded my expectations except for the one little issue of the smears. At any rate, the tech was able to realign the failed grommet and then silicone the hell out of it all the way from the center where the harness went through to the outside perimeter of the grommet where it sealed to the opening in the truck body. He took a couple pictures to show me exactly what they had done. Frankly I would have preferred to replace the grommet with a new one and left out the silicone, but to do that would have meant parting the harness in some way or at some connector, and that just wasn't feasible in this location. I'm OK with it since they did show me the pictures and I could see how it was the best option. Now you guys know I've always tried to emphasize this dealership has always treated me right, even disregarding how pizzed I was about the rubber cutout to fix the so-called seatbelt issue some months ago. I said then my issue was with Chevy/GM Corp, and not the dealership. I still feel good about this dealer, ever though it has changed hands in just the past while from when the seatbelt issue came up. The Srvs Mgr has taken my whole situation in hand and is trying to find some way to make my pain a little less. He knows how riled I was about the original cost of the thing, how particular I am about my truck, and understanding how it turned out to have been a bad call on the problem originally is looking to see what can be done. So, the bottom line is this .... Yes, it took a second trip and several more weeks to get it fixed, but I feel good about it now. I'm still a committed Chevy man and will remain so. Back when I was writing about the seatbelt issue, I finally identified the dealer as "Rossner" Chevy in Melbourne, Fl. Since those days, it has changed to "Boniface-Hiers" Chevrolet and I still feel good about the treatment I've gotten. It was a tough problem to find and then to fix, but I've got my truck back and I think it's all 'good to go'. So again I'll say ..... if you're ever around Melbourne, Fl and need some Chevy service, go see them at "Boniface-Hiers", formally "Rossner" Chevy. You won't be sorry.
Click to expand...
I know this is a super old post and I am at my wits end with what seems to be a similar leak for me. I cannot figure it out. I am guessing I have this issue. Did this fix the leak? Did you happen to take a picture of this grommet? Is it accessible from the engine side or from the interior of the vehicle or does the fender have to be removed to fix it? I started my own thread here a while ago and trying to fix the problem again now that I have a little more time - https://www.gmtruckclub.com/threads...eads/water-leak-passenger-side-blower-motor-fried-cabin-air-filter-wet.1475312/
 
#25 ·
jumpinjoe said:
OK, here's where I think we are. 1st, it rained this morning and afterwards all was dry. It wasn't a real hard rain, but enough I think to have shown up if it were still leaking. Now, as to how the water gets to the grommet. The best I can tell is that all the water runoff from the windshield and the cowl vents is collected in a 'trough' at the base of the windshield and under the cowl vents, right at the very back edge of the hood. And BTW, there is a pretty substantial rubber seal under the very back edge of the hood and all the way across that prevents any of this water from entering the engine bay at the rear of the hood. That water is then channeled to either side of the truck and falls down through the opening behind the inner fender, and in between the outer fender and the truck body. If you'll visualize removing the fender, what you would see is the side of the body directly below the 'A' post and at he front of the door. Between the wheel opening at the front and the door opening at the rear. I've really looked and see no other option. I have to assume that this is fairly common for the run-off water in most vehicles, I've just never thought about it before. I'm definitely not a 'paint/body' man. But, what I don't understand is that down in that open space between the fender and the body, I can see some kind of insulation that resembles 'rock wool'. Likely some kind of sound deadener. No doubt this insulation is impervious to water, otherwise it would stay soaked and lead to a bad rust situation on the inside of the fender. As for the harness grommet not being water proof, I think the design is that the wiring harness is pulled downward at the outside of the grommet and through-hole so that any water getting on it will drain away from the truck rather than follow the harness into the truck. Since I didn't actually see the actual grommet and was only told by the tech it had cracked/split, leads me to believe that when it cracked it allowed the harness to follow it's natural direction while under bend tension and to rearrange itself to an upward direction just enough to allow the water to flow into the truck instead of away from it. It wouldn't take much of a change in how that wire bundle lays. That would would explain why it (the leak) started all of a sudden. It's a hell of a chunk of wire (about an inch+ in diameter) in that harness and a pretty small area to be bent to control the direction it lays. I'm totally amazed at the design of the water flow from the windshield and cowl vents being directed down through the opening between the fender and the truck body, but after thinking about it, I don't know where else it could be channeled. There's just enough room between the battery and the fender to look down through that opening to see where the water is supposed to flow, and with a good flashlight it can be seen. I'd appreciate anyone who has a similar truck to look at theirs and see if they agree with my description. I'll be checking back from time to time till midnight tonight ..... after that the cable company is taking down our I-net service for some kind of maintenance. Won't be back up till early hours of the morning, but I'll be back again after that.

thanks and regards,
jumpinjoe
Click to expand...
 
Discussion starter · #26 ·
shahrkster said:
I know this is a super old post and I am at my wits end with what seems to be a similar leak for me. I cannot figure it out. I am guessing I have this issue. Did you happen to take a picture of this grommet? Is it accessible from the engine side or does the fender have to be removed to fix it? I started my own thread here a while ago and trying to fix the problem again now that I have a little more time - https://www.gmtruckclub.com/threads...eads/water-leak-passenger-side-blower-motor-fried-cabin-air-filter-wet.1475312/
Click to expand...
OK friend, here's the bad news. Unfortunately I did not get a chance to take a picture for myself. The truck was all back together by the time I saw it. However the tech working on the problem at the dealership did take some pictures for me to see. I was so excited to get my truck back I neglected to ask for copies. Everything is pretty much as I described earlier ... most of the front end has to be removed. Grill, bumper, light assembly, inner fender well, outer fender, hood, etc. The actual grommet is just ahead of the A pillar, about 1/2 to 2/3rds the way down from where the top of the fender would be. There's a whole bundle of wire about 1"+ in diameter encased in a rubber/plastic type of grommet that covers the wire bundle as it goes all the way through the trucks side structure and into the cab behind the passenger side kick panel. (I've never considered and had no reason to do it till now but you might be able to see it on the inside by removing the kick panel, I'm not sure.) It has to be waterproofed from the outside of the body structure to keep water from entering into the structure at all. I'm pretty sure the structure in question is double walled where the bundle goes through. I've not seen a drop of water since the repair.

Now for the really bad ... since you mention the cabin filter and blower motor got wet, I'm hard pressed to think the water came in the same as mine did. Thinking back on the pictures I saw and where I believe the hole for that wire bundle is located, I don't believe any water coming in through that hole could get to the filter and/or the blower motor. I could be wrong but I'm thinking that hole is a good ways below the level of the cabin filter and especially the blower motor. I'm guessing your leak is more up under the windshield or maybe, just maybe that air gasket between the heater air box and the firewall. It seems these windshields are susceptible to leaks under the edge anywhere across the whole width. A lot of responses to my original post mentioned that. As odd as that sounds as a spot to leak, it's far more likely that any water getting into the cabin filter and/or blower motor would come from that location. I'm thinking the hole where mine leaked is down below the level where any water could get to the filter, etc. Good luck and keep us up to date. jj
 
#27 ·
jumpinjoe said:
OK friend, here's the bad news. Unfortunately I did not get a chance to take a picture for myself. The truck was all back together by the time I saw it. However the tech working on the problem at the dealership did take some pictures for me to see. I was so excited to get my truck back I neglected to ask for copies. Everything is pretty much as I described earlier ... most of the front end has to be removed. Grill, bumper, light assembly, inner fender well, outer fender, hood, etc. The actual grommet is just ahead of the A pillar, about 1/2 to 2/3rds the way down from where the top of the fender would be. There's a whole bundle of wire about 1"+ in diameter encased in a rubber/plastic type of grommet that covers the wire bundle as it goes all the way through the trucks side structure and into the cab behind the passenger side kick panel. (I've never considered and had no reason to do it till now but you might be able to see it on the inside by removing the kick panel, I'm not sure.) It has to be waterproofed from the outside of the body structure to keep water from entering into the structure at all. I'm pretty sure the structure in question is double walled where the bundle goes through. I've not seen a drop of water since the repair.

Now for the really bad ... since you mention the cabin filter and blower motor got wet, I'm hard pressed to think the water came in the same as mine did. Thinking back on the pictures I saw and where I believe the hole for that wire bundle is located, I don't believe any water coming in through that hole could get to the filter and/or the blower motor. I could be wrong but I'm thinking that hole is a good ways below the level of the cabin filter and especially the blower motor. I'm guessing your leak is more up under the windshield or maybe, just maybe that air gasket between the heater air box and the firewall. It seems these windshields are susceptible to leaks under the edge anywhere across the whole width. A lot of responses to my original post mentioned that. As odd as that sounds as a spot to leak, it's far more likely that any water getting into the cabin filter and/or blower motor would come from that location. I'm thinking the hole where mine leaked is down below the level where any water could get to the filter, etc. Good luck and keep us up to date. jj
Click to expand...
Thanks for taking the time to reply and the guidance This is insightful. It was raining here today. I have had the kickplate removed and the top felt carpet pulled back to allow the water to dry. I noticed that the carpet was wet from the rain today, I did not catch any dripping water but it looked like water had dripped onto the carpet in certain areas. I agree that the water is not coming from the area you were experiencing it from and is coming from elsewhere - I felt the harness where it enters the cabin and it was noticeably drier than further down on the floor.

Image


Image
 
Discussion starter · #28 ·
shahrkster said:
Thanks for taking the time to reply and the guidance This is insightful. It was raining here today. I have had the kickplate removed and the top felt carpet pulled back to allow the water to dry. I noticed that the carpet was wet from the rain today, I did not catch any dripping water but it looked like water had dripped onto the carpet in certain areas. I agree that the water is not coming from the area you were experiencing it from and is coming from elsewhere - I felt the harness where it enters the cabin and it was noticeably drier than further down on the floor.

View attachment 178268

View attachment 178269
Click to expand...
From what I see I'm even more convinced your issue is from under the windshield ... or at least somewhere up higher than mine was. Keep us informed. Good luck.
 
#29 ·
Hey guys - Wanted to give an update on this real quick. Two things have happened since I last looked into this.

1. There is a water drain behind the right/passenger side wheel well - Not sure if this is by design or it happened over time - I believe that it is there by design (please correct me if I am wrong). I was doing some rust rework and paint and noticed there was a lot of crud that had gathered in there and so I believe the water was not getting out as soon as it should. However, I DO NOT believe that this is the issue because I saw water leaking in the passenger side irrespective. It is something that people should check into.

2. I redid the water leak test and this time with a lot of water in different areas. Water started leaking after it was pointed at the sun roof. I thought I had cleaned the sunroof drains prior but maybe not enough. Once poked, the drain seems to be allowing the water to pass through the right channels rather than into the passenger side.

Suggestions - ensure water is draining from all drain paths - behind wheel wells and the fire wall. Then pour copious amounts of water to check each spot - cowl, then around windshield, then around sunroof, then around antenna, etc and do so patiently. If water is not draining out at the rate it is going in, it might be welling up before it leaks.

I hope I have found my leak source (sun roof drains) and will keep everyone posted.
 
#30 ·
Well folks…I may have celebrated a little early. I did not however mark the task as “completed” on my reminders since I wanted to ensure this was fixed (not that it helps...lol)...ok enough nonsensical venting.....

I believe this is a two fold issues and I may have fixed just one of them. The other day it rained here and sadly the carpet was wet again. This time, however, I did not see any water dropping from below the A-pillar area. It was likely a blind leak that is occurring from behind the mat under the dashboard. For those not familiar with this, there is the floor board mat and then a mat that is at an angle under the dashboard. This mat has a plating/non-porous layer. Water seems to be getting under that somehow and going straight to the padding under the floor board. If anyone has any thoughts on how this may be happening, I am all ears. This leak is a b(&*^ch to figure out. Will keep the group updated.
 
#33 ·
finally found the source of the leak.

Started pouring water from the cowl up. No leaks from around the cowl, no leaks around the windshield. Tried the sun roof again. Nothing....until there was a slow drip again. First it started towards the front of the dash and then the rear. Slow drops but consistent. They lasted after I stopped pouring the water. This told me that the water was collecting in some area and then welling over. This confirmed that the leak had not been fixed from the last go around.

I poured water right into the drain holes of the sun-roof. When pouring into the passenger side, the water did not drain out as fast and there was the leak. The driver side drained just fine.

I used some 0.155in edge trimming string and pushed it down the drain hole to clear it of any debris. Seems like there was none and when pouring more water the leak was still there. I ended up removing the air filter and poured water. The leak was coming from above the air filter. Putting my hand in the air filter cavity, I found that the water was coming from the spongy gasket around the air intake passage. Looks like water is coming down the sun roof and collecting in that area instead of draining out. Will be removing the cowl tomorrow to take a closer look and see if I can get this figured out.

If anyone has schematics of the air intake for the cabin and that areas or if someone has fixed this before, please provide pointers.
 
#34 · (Edited)
SOLVED!!!

Alright guys....looks like I have fixed this. It ended up being the drain tube from the sunroof on the passenger side. One of the following was the issue:

1. The drain tube end somehow came removed from the elbow at the end and the water was essentially leaking into the back of the dashboard. I am not sure how they may have happened. Maybe improper install at factory (I doubt that) or it was removed either during a windshield change or someone poked the hell out of it during a clean up of the drain tube.
2. Or the elbow end of the drain tube can out of it location and part of the water was dripping into the back of the dash and the remainder on the other side of the firewall. My guess is that this is what was happening.

Reason why the water was going all over was:
1. The path of least resistance was the side of the dash (behind the fuse box) and that is where the initial drip started.
2. The secondary path was around the sponge/foam that would first create a dam, then get soaked and slowly give out that water. This water would find its way on top of the cabin air filter and then behind the dash.

Image


Here is a picture of what the end of the drain tube looks like.

Image



To fix this, I had to remove the A pillar covers and the upper part of the dash and just feel my way to put the elbow back in place. You can find that it is just behind the right passenger speaker on the dash. I ensured the end of the elbow was seated properly by feeling the way from the opposite (firewall side) - I had removed the plate above the air intake (under the cowl) for this. Once the elbow is in place, then insert the end of the tube into the elbow. It is close to impossible to have the tube inserted in the elbow and then put it in place. If I was to do this again, I would extend the tube.

Lessons learned -
1. GM designs are stupid. Just plain bad design. They needed to extend the tube further than then end of the elbow to avoid this. I would have cost them no more than a penny to add an inch or two.
2. Be careful poking the inside of the tube as it may push the elbow off
 
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shahrkster
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