Rear Plastic Window Fogging?

[tvacc]

Got a strange one here:

Went out for the usual LOONY breakfast meeting this morn...

On the way back...it looked like quite a thunderhead coming in the
direction I was going so I stopped by to put up the hood...

Now my car as no doors,as I have ths side protection bars...when I put up
the hood, the rear window was clear...I drove about 1.5 hours to get back
home..

When I go out of the car I noticed that the rear window was like fogged at
the top corners...I put my hand in there to wipe it out..and it is
permanently discolored..

What the hell could do this in 1.5 hours or driving...and what the heck as
I breathing in that is also doing this to the window...

Two variables that I just did that may be a hint to the problem..

On the way to breakfast..I hit the brakes hard and watched my oil pressure
disappear..so I was low on oil...must be that damn sandwich plate again...so
I thru in 1 quart..so I might be a little high on oil and getting some
blowing into the catch tank...

and...I just routed the gas vent lines to what I now think is a low
pressrue area by the right rear corner of the car...

Any Ideas?

Tony Vaccaro

93 Caterham...