ventilation problems with 90Q 20V

[Brian Powell <brian@owlscreech.com>]

Hello all,

I am having problems with my '90 90Q 20V: 

After driving for awhile with the heater on, when I come to a light or
stop, you can begin to smell (what seems to be) exhaust.  It has a new
catalytic converter, and there don't seem to be any exhaust problems.

I took it to my mechanic, he checked the ducts and so forth for the
ventilation system and said everything was fine.  He said to track it down
could get expensive as he would have to start taking things apart to get
into it.

Has anyone else had (or heard of) this type of problem?  Where would you
recommend that I begin doing my own investigatvie work rather than the
mechanic?

Second question: what cost should I expect for to replace the rear brake
pads and rotors (with genuine Audi parts and labor added)?

Thanks!

--Brian

'90 90Q 20V
'96 A4 2.8Q