"OK. Windshield, check that the cowl's water drains (on the firewall)
not clogged with dirt. "
You mean the drains that take water away from the area where the
winshield wiper motor is located and that serves as the air intake for
the heater? Covered by the chrome grill? I've been there, and water
flows right through there fine. Where it enters the cabin is at the
very top of the underside of the dash, just about where the window seal
would be located.
"Rear window - tough one, some glass shops won't touch it for fear of
glass breaking. "
Is this a problem with the windshield too? That's the kind of thing I
was wondering about. Plus how leak free, how long it will last etc. I
personally had a new car that needed a windshield and it leaked became
a problem. Plus I've heard from other people with similar experiences.
Think I would be better off trying to slip some silicone under the
edges of the existing seals? I was debating whether to try that, as I
figured it could make it harder to fix if I then decided to get the
seals replaced. The silicone would still be on the car where the new
seal would have to go and unlesss you were careful to remove all of it,
it would seem it could make for a leak with the new seal.