Rear window seal failure, Getting too hot from the Subie motor? Options

[theer]

Question for the intelligentsia:

My rear window seal failed on my Subie-swapped car, and I've noticed the firewall gets really warm. There's no backpad (yet), but there is a layer of sound deadening on the inside. No engine compartment pad, either. I can feel the heat radiating off the firewall. I haven't taken the temp, but I'd guess it's 120-130 degrees. Perfect for those 90+ degree summer days. The fresh air fan is not installed (yet) either, and my ice-powered swamp cooler contraption just can't compete.

Driving home yesterday, I noticed the window glass was actually warm to the touch and thought perhaps the heat is causing the butyl seal to soften and the weight of the glass pulls itself off.

I recently put the stock air flaps underneath in the hope that they would draw more cooling air through. No discernable difference.

Anyone else getting that kind of heat from their engine compartment? Would the engine compartment pad help? How do others get the heat to flow out?

Thanks,
Tom

[Superhawk996]

I'm going to suggest that the temperature is probably not your problem.

Butyl will easily withstand interior temperatures generated by sun load. Not uncommon to see interior temperatures as high as 160 F in Phoenix with full sun load, windows up.

Butyl has been used for years with these sorts of desert southwest, hot ambient / hot interior temps without having glass de-laminate from the butyl.

Maybe it wasn't installed onto perfectly clean glass and/or has become contaminated somehow? Likewise, the rear glass should be supported on the bottom by a couple small rubber pads. The Butyl should not be expected to bear the weight of the rear glass alone.

spacers are item #15:
http://www.autoatlanta.com/porsche-parts/h...;section=805-00



Specification for Butyl tape found quickly on-line:
Specification:

Solids: 100%
Service Temperature: -60°F to 275°F.
Application Temperature: 35°F to 110°F.
Bonding Time: Immediate water tight seal. Full bond in 24 hours.
Shelf Life: 24 Months
Tensile Strength: 25 pounds per linear inch.
Water Resistance: Excellent
UV Resistant: Yes
Cold Temeperature Flexibility: Excellent, passes 1/2" mandrel bend @ -60F.

I seriously doubt that your back window is going well beyond the max service temperature unless the exhaust and turbo are right there. If in doubt - measure the glass temperature and/or air temp right in the vicinity of the closed engine lid right below the glass.