RV Repair: Window leak?, silicone sealant, window leaks

Question
Can you answer a question on window leaks? I will ask, just in case you do.

We have a 1991 class C that has a leak in the front cabover window. We have caulked it up twice with clear silicone sealant, but it still seems to leak. I've called the two local trailer repair/dealers, and they don't do windows. Is there a trick to sealing these things up? Any helpful hints?

If you don't no windows either, thank you anyway. :)
Tina

Answer
Tina,

The first thing that you need to do is determine if the window is leaking around where it is installed or through the window itself.  If it's around were it is installed I would recommend removing the window and cleaning the old putty or foam gasket off completely.  Apply new putty around the frame of the window and re-install it.  Once that has been completed you will want to apply a cap seal to the top of the window.  We use a product called Quad.  It is a high performance window, roof and siding sealant that is basically a synthetic rubber.  Just apply about a 3/16" bead along the top and down the sides where the window meets the body of the motorhome.  With this particular product after doing that you need to spray it with a soapy water mixture before you smooth it with your finger.  If it is leaking through the window itself first check that the vents at the bottom of the window are not plugged up.  If they are take a small stiff wire and unplug them.  If they are not, then it may be leaking around the glass.  If that's the case it will need to be removed, and then the glass will need to be removed from the frame and cleaned and resealed in place.  Depending on the size of the window this can be a tricky task.  I hope this information helps and good luck with your project.

Darren