A/C service

[John Larson <jdlarson@ix.netcom.com>]

Good morning. I'm not an A/C service guy, and I sublet all the A/C
recharging work here at the shop. Several recent posts here prompted
this message. 
First: Any substitute refrigerant should be one listed and approved by
the EPA. There is a website that deals with this question, although I
don't know the address. Compatibility, functionality, safety, and the
chances of damage to the system are factors here, regardless whether you
buy into the "R-12 is environmentally harmful" argument. (I don't.)

Second: A depleted system should be evacuated and leak tested, both with
dye and with an actual vacuum holding procedure. Anything less is
throwing money away. One shouldn't just add a can or 2.

Third: Most modern systems do not utilize a sight glass, and the
refrigerant and lubricant are installed by weight, and the weights are
critical. It is, at the very least, difficult to judge the charge
without a proper scale. Any good A/C shop is going to have a machine (or
machines) which evacuates the system, tests the old refrigerant for
contamination, and accurately supplies the proper amount of coolant.

IMHO, failure to utilize the services of a trained, licensed,
professional A/C shop or tech to service the A/C in a modern car with
climate control (such as most of the cars on this list) is sheer folly.

Just my two cents worth, John