Community Forums

Gadget Man · 12-17-2014, 11:57 AM

I have a water leak that is driving me crazy. When it rains or when I wash my MH, I get a slight leak along the inside of the right half of the windshield. It’s always in the same exact spot. Thinking it was the outside windshield weatherstripping, I added silicone to the underside of the lip of the rubber windshield molding. This did nothing.

I know that rain can enter at one point and leak inside at an entirely different point, so I decided to try and isolate the windshield as the culprit. I applied duct tape around the entire top of the right side windshield, to prevent any water from penetrating the weatherstripping. It rained good and hard last night. I went out and the rain water still found it’s way inside at the same point. This leads me to believe that the water is entering from somewhere else, possibly the roof. A visual check of the roof reveals no obvious entry points.

I called a local RV repair shop and they recommend a negative pressure test. They would remove a roof vent lid and attach a high powered fan. They then coat the outside of the coach with soap and look for bubbles. The thought occurred to me, couldn’t I do something similar myself with a high powered fan inside the coach? Anyone try this?

Craig

jenandjon · 12-17-2014, 12:01 PM

I would bet one of the marker lights are leaking.

dennis45 · 12-17-2014, 12:15 PM

Quote:

Originally Posted by jenandjon

I would bet one of the marker lights are leaking.

I agree, I replaced all front and rear markers a year ago and during the process I found a couple that had been leaking.

In your post, you indicate using silicone to seal around the windshield gasket. Or at least that is my understanding. If you do some research on silicone, you will find it does not work at all with rubber.

dennis45 · 12-17-2014, 12:34 PM

I called a local RV repair shop and they recommend a negative pressure test. They would remove a roof vent lid and attach a high powered fan. They then coat the outside of the coach with soap and look for bubbles. The thought occurred to me, couldn’t I do something similar myself with a high powered fan inside the coach? Anyone try this?

A thought occurred to me. No, it wasn't overly painful.

Why couldn't you close all windows, vents etc and turn on you vent fans on reverse to draw air into the coach? Assuming of course they do reverse.
Maybe this would prove enough pressure to go outside with a bottle of soapy water and test for leaks. Good Luck.

MRUSA14 · 12-17-2014, 12:51 PM

I think a fan inside the coach will only circulate air around inside. The idea of a fan in the vent lid is to introduce outside air, which pressurizes the interior of the coach. That increased pressure will then bleed out through any openings or cracks and produce bubbles if you soap the outside. You could do this yourself if you can bring the air in from outside, but just having a fan inside the coach won't work.

dennis45 · 12-17-2014, 12:58 PM

Quote:

Originally Posted by MRUSA14

I think a fan inside the coach will only circulate air around inside. The idea of a fan in the vent lid is to introduce outside air, which pressurizes the interior of the coach. That increased pressure will then bleed out through any openings or cracks and produce bubbles if you soap the outside. You could do this yourself if you can bring the air in from outside, but just having a fan inside the coach won't work.

You misunderstood my post.
My suggestion was to turn on the existing Coach Ceiling vent fan, or fans, in reverse (which I believe most are capable of, I may be wrong) and thus have the fan or fans draw air into the coach. With all openings closed it will develop a positive pressure inside the coach which has to escape somewhere like a leak in the roof etc.

MRUSA14 · 12-17-2014, 01:07 PM

Oh, in that case you are on the right track. While that should work in principle, I don't know if the coach ceiling vent fans are powerful enough, or will supply enough pressure to do what you need. If you try it (and I would), please report back to the rest of us.

dennis45 · 12-17-2014, 01:36 PM

Quote:

Originally Posted by MRUSA14

Oh, in that case you are on the right track. While that should work in principle, I don't know if the coach ceiling vent fans are powerful enough, or will supply enough pressure to do what you need. If you try it (and I would), please report back to the rest of us.

Not knowing the details of the OP's coach, I know there is a difference in these fans. Some better than others,,,
I too would be interested in the results of such a test.

tunafish · 12-17-2014, 01:37 PM

I've seen people put a leaf blower in a hatch (vent) on a boat and seal around it by taping a black plastic bag around it. Turn on the leaf bower and it will pressurize the RV, put thick soap around some areas and you'll see the bubbles. Hopefully

**Lt Dan** · 12-17-2014, 04:39 PM

Quote:

Originally Posted by jenandjon

I would bet one of the marker lights are leaking.

x3 on the leaking marker lights. Mine leaked this summer for the first time in that same area, upper right windshield. When it was leaking and still raining, I pulled the inside windshield trim and the cabinet access to the roof and could not locate a leak anywhere. I checked the marker lights and found the foam gaskets underneath had compressed and hardened. Applied mastic under each light and screwed them back down with a little squeezed out around the edges. No leaks since the re-seal.

Gadget Man · 12-17-2014, 05:04 PM

Thanks everyone for the replies. I didn't think about the clearance lights, I'll give those a good look before proceeding.

Thanks guys!

Craig

Dutch Star Don · 12-17-2014, 10:01 PM

Gadget Man......I also think you probably have marker light issues. With that said, don't just seal around them. To do it right, pull them off, clean the surface and then put a large enough glob of silicone behind the light to seal the hole where the wires come through the fiberglass. Squirt some silicone into the two screw holes and then reinstall the marker light. Next make a nice clean bead of silicone around the entire marker.

Lastly, squirt some silicone over the two screw heads and then a small bead around the edge of the lens and install. You'll now be sealed completely. Sounds like a lot, but only takes a few minutes each.

Gadget Man · 12-17-2014, 11:15 PM

Will do, thanks Don.

Craig

adamfolger · 12-18-2014, 12:28 AM

Silicone does not stick to any surface for long. I would use plumbers putty in the screw and wire holes and a thin bead (roll it in your palm) under the marker base. No need to seal the lenses. That's what a good plumber will use to seal your kitchen sink to the counter. Lasts for years....just sayin