How should I address this window leak?

If a window is seldom left open, I use dielectric silicone grease in the slide channels. Downside is it does attract grit. Upside is woowee does it ever make the window slide easy and seems to repel water right out of the channel with the window closed. GOOP is way too strong for this fix so a gasket to body repair would be better suited for a black silicone.

... never mind

Naio did you ever get that window fixed or find the leak ? I am having the same issue.

Too bad you can't just address it, "return to sender." ;)

Thank you, all of you, for the awesome info! It helps to know where the common problems are. I will investigate further.

I was using a water hose, but will do it again (once things dry out) with more precision.

I can say that the channel us not filling up and overflowing. I will look for a route out of the channel to the interior, that should not be there.... or find that the water invthe channel is a watery red herring and the real leak is elsewhere.

I didn't think enough before, but realize now that if water is coming in between pane and glass it is going into the channel, and SHOULD be directed out again thru the weep hole, so that system is what matters.

I use 3M window weld when cleaning and resealing my dual pane windows. Sticks to glass, metal, rubber, etc.
Never had a failure.

Richard

Resealing the window BEFORE exploring other possibilities could be very frustrating as I've gone thru the same backward steps and will share my success only after having wasted efforts that had no success. My leak in a sliding window as well as fix windows revolved around the channel that the weep hole is part of. That weep hole allows the water that flows down the glass and diverted away from the glass by the rubber strip. Some of the water by gets behind the rubber cosmetic strip to collecrt in the channel that the weep hole is part of. Thru the years the channel will accumulate fine pollen like debris that sticks to the glass and washes down with the rain water. This debris will restrict the outflow of water even if the actual weep hole is clear. The channel needs to be cleand out, much like home rain gutters. The gunk in the channel will restrict the free flow of water to the weep hole and spill over the upper edge of the channel on the motor home interior side causing the type of leak you described. Pulling up the cosmetic strip will expose the channel for cleaning or for that matter to inspect to see if it does need cleaning. The cosmectic strip is very very easy to remove and replace using the same strip.

I have used www.parkin-acc.com for window parts. You will need to know the maker and model of your window as they have parts for many different windows.

I wouldn't disassemble the sliding part unless it seemed like that's where it was leaking in. I'd probably start with general inspections all around, pulling the rubber bit out of the channel--the one that's not seating all the way--and inspecting the path to the weep hole, as well as checking that the seals along and at the ends of the slider part are basically whole and not leaving a gap. The general theory is not that it's impossible for water to get past the seals etc., but rather that the quantity is quite limited and the channel lets it flow to the weep holes where it dribbles out harmlessly rather than collecting enough to get things wet inside. Since the latter is happening, either the water can't get to the weep holes properly or there's so much collecting in the channel that it is overwhelming the drainage system. I'd guess the former is more likely the cause of the trouble.

Obviously, it's good to have the slider part seal as well as it can when it's closed, not just for the sake of preventing water from entering but also to prevent drafts, bugs, and the like.

have you done a water hose test

mildly spray only the bottom half of the window
does water get in the track with the glass and leak inside,
or does it come out the weep hole

next try the top of the window frame ?

if the glass is loose in the track and not making a water tight weather seal

it could be a choice between permanently sealing the glass to the outside (not opening)
or getting a replacement window