Rear Window Leaking Again!!

PapaMikey

Member
I went to check on my trailer a few weeks ago to see how it was doing and I found water and wetness on the seat cushions and table. Not much my things were damp. I decided to dry things up and place a 2" deep plastic tray under the center of the rear window on the table. I knew that a rather big storm was coming our way and we were supposed to get between 2-3 inches of rain from this storm. The next day after the storm, I went to the trailer to find this plastic tray almost filled to the top with rainwater coming in somewhere along the top of the rear window. I could see droplets of water hanging on the inside window frame. I thought that this problem was fixed by the dealer, but obviously, it was not. I did notice that the sealant that was used is drying out and falling apart. I temporarily applied some new silicon sealant around the top window seal outside to see if this might stop the leak until I can do a better job of fixing this problem. I also noticed the sealant almost gone on the small window next to the entry door. I too applied new silicon sealant to this frame and hope that I fixed any problems with that window leaking.

My brother-in-law also suggested that I bring the trailer home, hook it up to AC, close the trailer up tightly, turn on the Air Conditioner and check for leaks around the windows with a soapy solution. Any bubbles on the outside would indicate where the air leaks are and most like where water is entering the trailer through the window frames. Good idea. I will have to try that, possibly in the spring.
 

cookie

Administrator
Staff member
From your description it sounds like your dealer didn't do a very good job of caulking the window.
Or it may just be past due for PM.
I suggest that you remove all the old caulk and re do it with a quality caulk. Silicon is not the way to go.
If you used silicon for your temporary fix be sure to clean the surface extra good.
Caulking needs to be inspected regularly and replaced as needed.
I would expect that a 2011 model to have been redone a couple of times by now

Peace
Dave
 

Westwind

Well-known member
Caulking on the top of windows and doors is equally important as the roof, also all joint caulking. Especially if you have slides. My Bighorn was built April 2011 and I've checked and caulked where needed on the roof and windows. I also did some wall and slide caulking this fall but I have a long way to go, I'd say about 1/3 of my caulking needs to be replaced.
Just like a house, on going maintenance.
 

branson4020

Icantre Member
Yes, all that caulking is important, but, the caulking along the top edge of the window frame is not what keeps water out. There should be putty tape or a gasket between the window frame and exterior wall. Also, I don't know exactly what an MPG looks like, but is it possible that water is getting into the wall higher up, say from clearance lights, or a roof seam, and exiting at the window frame?
 

wdk450

Well-known member
The AC/soapy water test is a move in the right direction, except for the fact that the air conditioning has an inside return vent, and therefore the AC does NOT pressurize the inside of the trailer in relation to the outside atmosphere. The pros who do this test pressurize the inside of the trailer with a fan blowing in from the outside sealed up against a roof vent or side window as tightly as possible. You can fabricate your own sealing with cardboard, duct tape, foam rubber, etc. You just want to minimize leakage air at the pressurization point. Also, other roof vents and loose slide seals make totally sealing up the interior pretty difficult, and call for a BIG fan source.
 

ryanman

Member
Check out my wet seats in Wyoming thread in general discussions. I figured out the fix and have pictures. Good luck.
 

jearnest

Member
Our 180 MPG had to have the front and rear windows replaced (under warranty) in 2013 due to water leaking through the seals. Shorty after the repair was completed we left on a trip to Alaska. On the first day that we encountered rain on the trip the windows were leaking again. Took the unit back the dealer when we returned home and they resealed both windows. No leaks to date but then again its been rather dry here in SoCal. I checked the unit following the last two rain storms and the unit is still dry. Will post what happens going down the road during a rainstorm.
 

PapaMikey

Member
Thanks for the ideas. I have noticed that the caulking around the windows appears to be putty. It has become quite brittle now and I will bring my trailer home and spend an entire spring day taking out the old and putting in new sealant. Our summers here in NoCal are hot and I am sure that is what is drying up the caulking. Not sure yet how to fix the back window leak, but if can't do it myself, I will be taking it to a dealer. Perhaps not the same one that fixed it before, but find one that is more likely to do a better job. Thanks everyone.
 

Westwind

Well-known member
We spend 4 months in the hot Florida sun and I think it really does a job on caulking of any kind - it all needs a serious check at least every two years because that seems to be when it begins to deteriorate.
 

PapaMikey

Member
I have been traveling back and forth to our trailer to check on it and it still leaks. After the rain stopped for a day, I was able to totally cover the rear window with plastic and duct tape until I can really get to it this spring. I also found a leak going into the storage box next to the entry door on the left side of the table. I traced it to water getting in around the right rear stop light assembly. I pulled off the plastic chrome bezel and removed the light fixture. I looked into the hole where the wires are and it was wet inside. I also suspect that water might be coming in through the three upper marker lights on the rear end of the trailer. I covered those also with duct tape for the time being and plan on replacing all the sealant on ALL the windows and lights come this spring. I found a website that explains how to remove all the windows, remove all the old dried up sealant and replacing it. I am not sure if I want to tackle this job on my own, or to have one of our "trusty" RV repair facilities do it. I guess it depends on how much it will cost me to have them do it. While I was tinkering around with my my problem, a fellow trailer owner came up to me and he told me that he has had his unit for ten years without a window leak problem. I looked at his window seals and they look nice and in good repair. My trailer is just over three years old and I am already having to do all this work. Stay tuned friends.
 

caissiel

Senior Member
I had a window leak on one on our new BC. I removed it and found it was leaking from above. The roof was leaking at the gutter location. Removed it and found fasteners not holding tight.
Installed longer stainless screws and everything is ok now.

The wall rotted on a previous unit that leaked by a window. So find it and repair ASAP.
 

PapaMikey

Member
Hello again. I found out through trial and error that the rear window on my MPG 181 was not the source of the water leaks. I had masked off the rear window with a couple large garbage bags and duct tape. Soon afterwards, we had more rain come through and I found a lot of water in the plastic bins I left on the dining table under the window. What I did find out was that the sealant was almost non-existant around the three upper rear marker lights above the rear window. The rain water was traveling down the roof line, running in through the three marker lights, traveling down the interior roof line and dripping out through the top of the inside of the window. I used duct tape to temporarily seal the upper portion of the lights and that stopped the leakage. I also noticed the sealant had deteriorated around the right rear break light housing, allowing water to enter the light and travel down the wires. This caused the dampness inside the storage box near the front door and dining table. I am sure now that the rear window is not leaking at all and the original culprit were the lights. I purchased some good RV sealant and proceeded to reseal all the lights on the trailer after the temps got back up into the 50s. I also noticed that the putty sealant along the top edge of the window next to the entry door had also deteriorated, leaving a large gap in the seal to allow rain water to flow into the trailer.

I removed that window using instructions I found online and proceeded to reseal the window. When I got the window off, I found out that there was NO putty sealant around the window (like other trailers use). Instead, I found a rubber seal and a smidgen of caulking around the window frame. My window now has a good putty-tape seal around the entire window. I found out that this window removal and installation is much easier if two people are doing it. Maybe it is just my trailer, but I am surprised that the sealant around the lights and windows is deteriorating within 3-4 years of manufacturing. I suggest that everyone check their lights to make sure they are still sealed properly. It could just be the hot summer days here in the Sacramento area, but I guess I will have to start checking the sealants every year before the winter rains come, that is if we get any rain at all here in California.
 

danemayer

Well-known member
I am surprised that the sealant around the lights and windows is deteriorating within 3-4 years of manufacturing.
The trailer manual says to check the sealant on roof and sidewalls every 90 days.
 

gahorn

Member
I have been traveling back and forth to our trailer to check on it and it still leaks. After the rain stopped for a day, I was able to totally cover the rear window with plastic and duct tape until I can really get to it this spring. I also found a leak going into the storage box next to the entry door on the left side of the table. I traced it to water getting in around the right rear stop light assembly. I pulled off the plastic chrome bezel and removed the light fixture. I looked into the hole where the wires are and it was wet inside. I also suspect that water might be coming in through the three upper marker lights on the rear end of the trailer. I covered those also with duct tape for the time being and plan on replacing all the sealant on ALL the windows and lights come this spring. I found a website that explains how to remove all the windows, remove all the old dried up sealant and replacing it. I am not sure if I want to tackle this job on my own, or to have one of our "trusty" RV repair facilities do it. I guess it depends on how much it will cost me to have them do it. While I was tinkering around with my my problem, a fellow trailer owner came up to me and he told me that he has had his unit for ten years without a window leak problem. I looked at his window seals and they look nice and in good repair. My trailer is just over three years old and I am already having to do all this work. Stay tuned friends.

What is the link to the website re: window removal?
 

jmgratz

Original Owners Club Member
Check the caulking around the edges of the roof. We found some areas on ours that needed recaulking that leaked around the rear window. We thought the window was leaking but turned out it was around the edges of the roof just above the gutter line.
 

PapaMikey

Member
I found the culprit. The three marker lights above the rear window were the problem. I checked and found that most of the factory caulk had disappeared and water was getting in behind the lens caps. That water was running down the inside of the roof, down to the top of the window on the inside and dripping on the table. I also found a problem with the caulking or seal around both break lights, so I spent one afternoon, recaulking everything including the side marker lights. Now, there are NO leaks (knock on wood), and I hope that this new caulk is better than what the factory used.
 
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