Hi All:

The rainy season has begun in earnest here, and for a 2nd year in a row, I find myself searching for a leak that is soaking the passener floor of my beloved 1985 GL (240) wagon. I have the passenger seat out, all of the carpeting up and drying (no rust yet!), and most of the dashboard pulled apart for inspection. One leak has been fixed (the computer harness leaked at the firewall gasket and was caulked), but there is another somplace. I've eliminated the windshield as a posibility (resealing that was last year's leak project) using the following logic: when I tape up the fresh air inlet grill and deluge the windshield, the inside remains dry. So it can't be the windshield. As soon as I remove the tape covering the air inlet, a trickle begins inside along the firewall starting from way up above the HVAC unit. I've resealed the windshield wiper gaskets (new gaskets are on order), so I don't believe they're it, although my sealing job could be faulty. The HVAC "S" drain tube is clean and bone dry - even after leak testing. Is that suspicious?

So, I'm left to think that the gasket at the top of the HVAC unit is leaking. That problem was reported here some time ago. My question is, is there a way I can be more sure that's really it before dismantling the entre car? Is there anything else it could be? I only have a dim idea of how the heater/air conditioner is constructed and what the air and water flow is supposed to be like. Is there a recommended resource that can help me understand how this all works?

Thanks in advance for any info.

DC