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Re: TQC heater core replacement

   Hi all,

   It seems that the heater core on my 83 TQC is leaking. I first noticed a 
   slight window fogging while running the heater/defroster. I finally shoved 
   my hand up in front of the center console, and much to my disappointment, 
   the carpet was wet with coolant. Sooo, has anyone done this work on a 
   4000/coupe/TQC? Difficulty involved? Tips? Is this a DIY job or better to 
   let the pros handle it?

Make sure it is coolant (smell and feel should be pretty obvious - that
stuff is downright VILE! which is why I find it surprising that the car-
pet could get wet without your having smelt it first...). It's also damn
slimey! (assuming you're not running straight water)

The A/C drip tray fits into this stupid little "boot" which kinda more
or less channels most of the condensate "overboard" into the engine com-
partment and thence down to the ground. Someone had incorrectly re-in-
stalled my drip tray so that it was positioned *under* the rubber boot,
so it conveniently dumped most of the condensate down "behind/underneath"
the carpet.  Since the carpet has a rubber backing, the carpet itself was
"dry", but when I pulled it back to "investigate", the entire underlayer
was SOAKING wet. I suspect it had been that way forever... I really ap-
preciate Audi's rustproofing...

A "slight" fogging when first engaged is quite common to car heaters,
although I've never completely figured out why; every car I have ever
owned has done it.

Also, another "gotcha" that got me (re fogging up windows *and* wet
carpet) is that some [probably the same] a****** had broken off the
little vacuum nipple to control the fresh air vacuum servo on the AC/
heat control pod, so had "wired" (plumbed?) the servo directly to the
vacuum line, effectively locking the fresh air vent closed. On short
trips (10 minutes to local office), no problem, but on longer trips
(20 minutes) the windows fogged no matter what I did, and by 30 minutes
the windows were dripping wet! (#^%@(#()@*#)!!*&^!). I *had* to drive
with window open and heater full blast to keep me non-frozen and the
windows clear. Audi, in their infinite wisdom, of course disallow run-
ning the AC and heat at the same time (*I* have since fixed that in my
car), so you can't defog the air . . .

Of course, on the principle that the most expensive and complicated
solution is probably required (which certainly has characterized most
of *my* UrQ problems), the heater core *is* leaking. I'm 99.44% sure
that you have the take the whole effing car apart to get to the core.

Good luck!