How come it only leaks when I'm towing?

[Brian G.]

It's my front window, the one beneath the rock guard. While stationary it can rain cats and dogs and we stay bone dry inside - even when the wind is very gusty. But if we are towing in the rain that same window lets in a lot of water. What explains this?

[David Tilston]

Air pressure pushing water in cracks that would otherwise drain.

[Brian G.]

Interesting. Well, I guess I'd better eliminate those cracks. Does this necessitate removing the window?

[John in Michigan]

Brian, it might help to post a couple of pictures.

Have you tried testing with a garden hose from different angles?

We have found and fixed leaks that only happen when stationary, and only during a very heavy rain. Sometimes difficult to duplicate with a garden hose...

John

[John in Michigan]

And we have definitely eliminated some leaks by removing and resealing with butyl tape. But other window leaks depend on the window type.

[Brian G.]

The leak is primarily near the lower left corner. Applying silicone and sticky putty to the inside stopped water from the garden hose, but not rain water while towing on the highway.

[John in Michigan]

If its a slider window, several measures can be taken. Completely remove and reseal the window with a thick layer of butyl tape, so that it oozes out when you reinstall the window. Next, make sure that at the bottom of the window, water is flowing freely out the weep holes/slots. To achieve this, spray water into the lower track, up through the weep holes, etc. Use mono-filament, wire, etc. to unclog the weep holes.

[John in Michigan]

Beyond that, since the window is located on the front of the camper and its leaking while towing, I would look at ways to modify the rock guard to channel water away from the window.

[Brian G.]

Yes, it is a slider window. I carefully inspected the weep holes. They are clear. So, I guess I'll be removing the window and applying the butyl tape. Thank you.

[John in Michigan]

Also, for a slider window (or fixed pane window), we have found with our 40 year old Boler 17 that you have to look at the seals on the window assembly itself. For our Boler 17 slider window sashes, the sealant around each window pane (piece of glass) had largely disintegrated. The panes had to be removed, glass and frame cleaned, and then the panes were reinstalled with new sealant. The sealant can be either very narrow 1/4" butyl tape, polyurethane glazing tape, or glazing silicone.

[Brian G.]

John, did you do that work yourself? It sounds pretty time-consuming.

[John in Michigan]

It was an adventure. As with any old camper, when we first got it one of the top priorities was making it water tight. We determined we were going to have to remove and reseal all 7 windows (incl. door window). So we did that last year. In the process, two of the windows needed the glass resealed. A shop did one of them after we had broken one of the panes. We resealed the second window ourselves. We are also replacing the rubber outer seals in all of the window sashes. We found a rubber outer seal product that fits when we were half way through reinstalling the windows. So we plan to go back and install it in all of the windows.

[John in Michigan]

While I'm on the subject, your third photo shows that you put putty behind the rubber seal that rests against the window pane. That rubber seal holds the pane in place, but it doesn't seal it. The sealant is actually on the opposite side of the window pane (1/4" butyl or glazing silicone or polyurethane glazing tape or ...). So if you see water seeping through that rubber seal, the window pane needs to be removed and resealed.

[Tom 72]

In addition to air pressure, bouncing down the road and flexing likely causes cracks to spread momentarily.

[varmint]

We own a 1997 16' scamp. Mine does the same thing. It can rain for days at a campsite and there is no problem. When traveling south this past Jan, we drove 2 days and maybe 600 miles in the rain at 65 mph or so. We have the full size non-slider front window with the gravel shield. Knowing it leaks, I wipe the lower window area about twice a day with a hand towel. It leaks just enough to leave the towel damp.
When we bought the scamp about 5 yrs ago, I was told the front window had been cracked and replaced. The seal is a rubber grommet type with grooves for the body and window. I ran blue masking tape along the window to catch the surplus and ran a plastic putty knife along the seal to open it for some clear silicone. I did this because the "hose test" produced a slight leak which was gone after the seal job. Don't forget the spot where the two ends come together at the bottom. 65-70 in the rain for hours means the hand towel wipe down every few hours. Fact is I don't like driving in the rain and will avoid it if possible.

[Brian G.]

George, I might just adopt your wipe-down-with-a-towel method for the next few months. It would be disappointing to miss out on the camping season because I've got my windows removed and sitting on the garage floor.

John, thanks for your detailed advice. I'll pay closer attention to the way my window pane and window frame are sealed.

The pathways of water can be mysterious.

[Gilles]

On our Bigfoot, I had this problem of water but stopped only with a good rain.

I noticed that the water coming down from the roof was concentrated in the center of the window and that the small drains, in the sliding windows did not provide emptying in their turn and that they overflowed towards the inside of the window to make us occasional small water damage.

I used a self-adhesive rubber gutter, fixed around the window much like the picture and the problem disappeared.

[Gilles]

Originally Posted by Gilles

On our Bigfoot, I had this problem of water but stopped only with a good rain.

I noticed that the water coming down from the roof was concentrated in the center of the window and that the small drains, in the sliding windows did not provide emptying in their turn and that they overflowed towards the inside of the window to make us occasional small water damage.

I used a self-adhesive rubber gutter, fixed around the window much like the picture and the problem disappeared.

I used the dark, black strip gutter, as the window turn is very dark brown, the gutter is virtually unapparent.