90q heater core --- symptoms and BTDT?

[Andrei Kogan <abk@phy.duke.edu>]

Hello,

I think we got a leaky heater core, or something in there. I would like to
order it and do the work next weekend, and have a couple of questions.

1. Is my diagnosis right? When I turn on the heat, I can smell antifreeze
and the windshield fogs up. The problem is, I don't see any physical leaks,
and the level doesn't drop noticeably. Maybe, it's a very small leak.

2. I would kinda like to get the core before I start, so I don't have to
wait for it with the car disassembled. However, I wonder if there are other
parts in there that are likely to leak coolant. Connecting hoses, for
example. Can I be pretty sure that the core itself is the problem or should
I take the dash apart first and see what is wrong?

3. What else should I replace along the way ? Foam, gaskets, o-rings, or
some such items? I have no idea what it looks like inside, any suggestions?
I heard many people experienced problems with rotten foam which either
allowed heat to escape from the vents before delivering it to the passenger
compartment, or allowed the hot and cold air to mix. 

4. How do I wash off the nasty stuff that ended up on the inside of the
windshield while we ran the heater for a little while? I am presuming its
the antifreeze vapor deposits, nasty, nasty greasy stuff which make the car
inoperable at night because of glare. I tried windex with no luck. 


5. It seems that the 80/90 heater is a weak point, compared to the 4k. I
haven't seen any posts regarding the 4k core leaks, yet for 80/90 there are
plenty, and those are newer cars. 


6. Anyone who worked on the heater core in the 80/90 (ours has A/C) please
let me know if there are any special things to watch out for. If anyone has
a step-by-step procedure, that would be great!


Many,many thanks.

Andrei