Subject: Re: Conversion to R-123A on My 1991 20V Turbo

[Tony Hoffman]

Also, if the compressor blew up, you will need to replace the expansion
valve/orfice tube. They typically get plugged with metal shavings. I've
never had any issue with a condensor plugging up due to a blown compressor.
We do back flush everything when a compressor goes bad.

If this was on the V8, consider yourself lucky. The Condensor design is
larger and more efficient than the I-5 type 44's. Still serpentine flow,
though. Just did a conversion on one (1989 100), 55 degrees at idle at
90deg ambient temp. 48 going down the road. I'd suspect that will rise to
65+ at idle when the temp goes above 100.

You don't "need" the fittings for R134, you can charge an R12 car with the
complete R12 guage set. BTDT. If you are using the small cans, get a side
can tap, and there is no need for an adapter.

The vacuum pump is used to evacuate the moisture out of the system. Not
100% necessary, but a very good idea.

R134 fills to 80% of R12 capacity. So, if your car took 2lbs, multiply by
.80, and you will use 1.6 lbs of 134.

Yes, I feel I've had to learn way more than I ever wanted to about A/C
since moving to TX :(  Five cars at the shop right now for A/C work.

Tony

On Mon, Jul 1, 2013 at 2:46 PM, Mike Arman <Armanmik at earthlink.net> wrote:

Just did an A/C repair on another car . . . here's what I learned.

1) Everyone will tell you that your old R-12 gauge set isn't good for
R-134, see, the fittings are different, and we have a new set for only
$(fill in the blank).

You can buy an adaptor set from fleabay for about $20. There's an adaptor
for the red hose and one for the blue hose, they screw onto the hoses and
have the correct R-134 snap fittings. You also need an adaptor for the
yellow (supply) hose - I paid $5.00 including freight for that one, so for
$25 I had an R-134 gauge set which I can still use on my R-12 car and R-22
home A/C, etc.


2) Everyone will tell you that you need to buy a vacuum pump. Advance Auto
will "rent" you one for $0.00 for a month. You put it onto a credit card
and if you can get it back to them inside of a month, you get a full
refund. If you are late, you get to keep it ;-) but alas, they'll keep the
money.


3) Everyone will tell you that you need a new condenser. This is true if
the old compressor has grenaded because sometimes you can't clean the
condenser out (won't back-flush). If the system was working properly or
just leaked out but didn't fail spectacularly, you don't need to buy this,
keep the money.

4) You DO need a new receiver-dryer. These scavenge any residual moisture
from inside the system. Best place I have found is Rock Auto, after
shopping VERY carefully. Mine listed at over $100 from the stealer, $60 at
FLAPS, $11 from Rock Auto - fits and works perfectly. Comes in a generic
white box . . . I can live without a pretty box seeing that I'm just going
to throw it away when I'm done anyway.


5) READ and UNDERSTAND the various instructions. They are poorly written,
vague, imprecise and misleading. Better yet, get two or three instruction
sets and compare them. There is a series of steps which must be done in
order, and the various valves on the gauge set must be opened/closed in the
correct sequence or you risk blowing the compressor. (Don't feed liquid
freon to the high pressure side, kaplooie, don't open both valves on the
gauge set simultaneously during the charge sequence, the only time they are
both open is during the vacuum process.)

6) Don't overfill the system - more is not better. There's a specification
somewhere (mine was 22 ounces) and of course each can has 12 ounces in it.
You can do this with a scale (weigh an empty can, compare with a full one
to determine the weight of the freon in a new can), or be content to
underfill slightly (worked for me).