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

[Mike Arman]

> From: Paul Caouette <paxnobis at gmail.com>
> To: Jeremiah Curry <jeremiah at curryclan.net>

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


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).

So far, I'm getting 42 degree air, no leaks, no nasty noises, but I've lost 4 mpg. I suppose I can 
live with that, it tends to get rather warm in Florida in the summer (but nothing like Vegas is 
getting right now!)

Original quote to fix the A/C was "$500+/-, perhaps a bit higher". Net cost to me for expansion 
valve, dryer, set of spare o-rings, ester oil, gauge adaptors, everything, was under $80 including a 
$10 cabin air filter, and it took me about two hours. Wasn't even hard, just go slow and think 
things through. Did skin my knuckles a little bit though, access was not very good.

Best Regards,

Mike Arman
90V8Q, others (with cold A/C)