t44 with ND compressor, 134 updates and whatnot

[James at ringsperformance.com]

Haudi,

The car, '89 200q (MC1), 7-blade fan/rebuilt motor, ND compressor, pearl
white with 50% window tint and black leather.

AC needed service as it leaked out its charge from the previous service in
only 18 months. Hmmm, what about Autofrost, "an approved R12 replacement."
YMMV, but it didn't stay in my 200 (requires barrier hoses, not evident
until you read the EPA's fine print), and it destroyed the front seals in my
beater 4kq (York) and Henry's '88 (?) GTI.

My NipponDenso 10P17C compressor was mechanically OK but weepy. I renewed it
with a seals kit from www.acsource.com, something like $20. If your
compressor has run dry of oil and seized, it cannot be repaired for less
than $14,732. Get a "good" one from a yard and rebuild that. I flushed all
the lines (carb cleaner and compressed air), replaced the receiver/dryer
(sometimes called the accumulator), replaced all O-rings, and installed a
"heavy-duty" variable orifice valve from acsource. I then evacuated the
system, filled with ester oil, and charged with R134 until best temperature
performance was achieved (I do not have a weigh scale).

Temperature results from a recent drive through Nevada, ambient 91 dF,
dewpoint somewhere around 40 dF, two adults and two kids in the FULLY-loaded
car, oil temp ~125 dC, cruise set at 80 MPH, climate control set on "lo,"
fan on "lo," I measured 46 dF from the center vents after five minutes;
running the fan on "hi" netted 43 dF from the vents after five more minutes.
If I am driving at speed and start the AC, it takes no more than 5 seconds
for really cold air to issue forth from the vents. (The oil temp is relevant
on my car because I have relocated the muffler and installed a large oil
cooler in front of the condenser, which makes the apparent temp higher when
felt by the condenser, reducing system performance. See
http://www.ringsperformance.com/filter3.jpg and
http://www.ringsperformance.com/filter4.jpg).

In reasonable temps of 80 or less, if I rev the car past 2000 in the
driveway, the vent temp drops down to ~41 dF and the compressor cycles off
("freeze" warning sensor in evaporator is triggered). I am completely happy
with the R134 upgrade on my car. I paid $20 for the seal kit, $10 for
O-rings, $25 for the HD VOV, $45 for the dryer, $4 for oil, $5 for
refrigerant (I bought a 30-lb bottle for $60), and invested some time.

THE MOST DIFFICULT job was getting the evaporator/dryer connection loose.
This is a copper/aluminum joint under the plastic cover behind the firewall,
which seems to suffer galvanic corrosion or hatred from the Audi gods. Some
heat (the joint is all metal, just don't melt the plastic evap surround), a
bit of lube, more heat, some time, a few well-chosen epithets, and a bit
more oily heat got mine loose. On another car, I had to hacksaw the ALUMINUM
nut off the dryer to spin that part off the non-rotating copper. Then the
copper cooperated for a reassembly with the new dryer. You may be able to
cut the copper and reassemble with a plumbing compression fitting. It seems
the dryer "must" be replaced as it allegedly contains a desiccant which will
dissolve in 134, clogging the system and ruining the compressor. Your
results may vary.

Naturally, YMMV, but it worked (works :-) for me.

James Marriott
'84 4kq beater, 217k, for sale (BUY IT!)
'87 4kq (alias "late-B2 90q") with rare ersatz NG engine, 184k
'89 200q (MC1, ProconTen/no bag, 1.8 blah blah), 142k
Boise, ID, USA     http://www.webpak.net/~marriott/
www.ringsperformance.com