Help Finding A Phantom Rain Leak

[RoryTug]

I have a 2011 Itasca Sunova 33c.

Living in Las Vegas, NV, my coach has not seen much rain in the year we have owned it. Over the past couple days, it rained hard and steady for prolonged periods and yesterday, it rained for 6 hours straight. I had the coach A/C's on and was working inside and noticed water on the dash. I traced the leak to the side cabin windows (both driver and passenger). The water was leaking from the same place on both which I will try to describe. The window is split. A small fixed 6" tall single glass over a sliding window on the bottom in what appears to be a single frame. The water was coming in from the uppermost front corner of the window frame. It appeared to be coming from behind trim flashing on the inside.

Today the sun is shining so with my ladder, garden hose and wife in tow, I set out to find the leak. I soaked the window frame...nothing. I soaked the running lights, roof antennas A/C mounts EVERYTHING I could run a hose on and not a drop. Anyone have any ideas?

[tbutler]

In the process of testing did the windshield gasket get a good soaking test? If the windshield top gasket is higher than the side windows, that may be your source.

[RoryTug]

I soaked the whole front of the coach from the roof starting at the sat dish and working down all the running lights and window seams with a running garden hose for over 30 minutes.. I am befuddled.

[tbutler]

How much water leaked in? We had water dripping on the dash of our coach when we first received it. That was associated with cold weather when the outside shell of the front cap was cold. We determined that the water was condensation which would then drip onto the dash. The quantity was never large. We had the front cap above the cabinets insulated, problem solved.

That said, your situation doesn't sound like it would be a condensation problem. I mention our solution only because of the similarity in the location where the problem occurred. In your case, with the air conditioners on, the inside air should have been dry enough to prevent condensation. I addition, Las Vegas doesn't get cold enough to cause condensation and of course the air in Las Vegas is normally quite dry, I suspect even in a driving rain the humidity in Las Vegas is probably 20% .

I do know that a roof leak can travel a long distance before it finds a route into the motor home. We had a leak from the large awning which would drip from the front air conditioner. Once we got it sealed well we had no more problems.

Happy hunting!

[tbutler]

I just thought of one more possibility. Our coach routes the condensation water from the air conditioners to a tube which runs inside the ceiling, down the post beside the windshield (for the front AC) and under the coach so we normally don't have water dripping on the roof and running down the side of the coach. When ours clogs up it starts to run across the roof and I have to go clean the drain. If yours is similar and there is a way for that water to leak inside, perhaps the water could have been condensation from the AC. You may not notice the problem in the normally dry air of Las Vegas but with higher moisture it may have shown up.

[wdterry]

Have you had a 'water test' done on your rig ? A good RV body shop can install a temporary entry door with a high pressure fan - the rig is pressurized, and the outside is checked for air leaks. If air can get out, water can get in. I have our rig tested each spring when it comes out of storage - the small cost can save a lot in the long run.

[campcop]

I had a similar leak when we first got our Vista and it appears that you have the same type windows. I noticed our leak only in the drivers side window and only found it by chance when after washing the rig, decided to clean the inside windows. I found water in the bottom rail. After searching on a step ladder, I found that the front cap trim that was over the drivers side window had a small gap that had not been caulked with clear caulk...used a clear Big Stretch caulk that does not shrink and will stretch. Problem solved, no leaks after a summer of rain in the northeast.