The AC on my 92 LT1 has stopped putting out cold air. I'm ignorant about how to correct the problem. Does this require replacing the entire unit or can it be recharged? I understand that vehicles manufactured before a certain date need to upgrade to a ozone friendly refrigerant which can be expensive.

 

Depends on what broke or why it leaked out. A quick check is to look on the underside of the hood, above the compressor. If it's covered with a line of oil, the compressor shaft seal is shot, a common failure on the Nippondenso compressor in your Vette. The compressor is about $400 to $500, or you can try to replace the seal - about $50 with kits available at NAPA.

The original refrigerant - R12 - is available, about 15 Bucks per 12 oz can at Autozone - you'll need 3 (for a complete charge) and a license to buy it. It can be converted to R134, no license needed, and you'll only need maybe 2 and 1/2 cans - about 8 to 10 Bucks/can. Conversions take new fittings (so that the Manifold Gage Set hoses will hook up and that the next owner or shop doesn't get the wrong idea about what's in it), a new Accumulator/Drier and the Orifice cleaned or replaced plus whatever part is making it leak. You also need to add some compatible oil (different gases take different lubricants).

If you want to get licensed, go to www.epatest.com and take the online exam.

If you know nothing about a/c, you probably need a little bit more, so at least get a Shop Manual - consider an Adult Ed class if offered in your area. I would take it to an a/c shop to find out where the leak is (if it isn't obvious - Pep Boys usually runs an ad in the summer time offering a "performance checkup" for about $25 - maybe more now that it's cooled off and there's less a/c work). Expect a 25 to 50% markup on the price of the gas (and parts) at an independent a/c shop - even more at a GM Dealer (where, for example, the compressor lists for $800 or so).

To do the job yourself, assuming it's empty and something has to be replaced to fix it, you'll need a vacuum pump (to suck out all the air and moisture that's in it) and a manifold gage set to get it recharged. The gage set will show you what the operating pressures are and in the automotive a/c world, pressures are everything. Good sets are about a $100 and the hoses are different depending on whether you're using R134 (the new stuff) or R12 (the original). Some places rent Vacuum Pumps. A decent one costs about $200 OR if you have a 5 hp compressor with a good size tank, you can buy one that runs off of compressed air for $10 at Harbor Freight Tools. Some enterprising souls have jury rigged the engine's PCV hose to the Manifold Gage Set using engine vacuum to suck out the moisture in the a/c system. I can't recommend it, but if you want it to cool again and not waste the a/c compressor, you've got to get the air/moisture out of it before you put any gas back in it.

Hope this helps - find out what's leaking and then weigh the options.

 

online test Hmmmmm

 

"online test Hmmmmm"

Beats going to Mexico and trying to sneak it across - even if it's only $3/can in TJ (and the rumor has it that most of the a/c shops in this town get the majority of their R12 from there anyway). Remember too that there is no license required to do automotive a/c work. Anybody can walk into Wally World and buy all of the R134 they want along with a charge hose. Nor is there any requirement that a leaking system has to be fixed or that any new system has to be leak free (probably because the OEM's can't make one). The licensing requirement is simply to buy the stuff - nothing more - and if you go here and poke around you will find a list of all the places you can go (online or otherwise) to get that license (that's how I found it):

http://www.epa.gov/Ozone/snap/refrig.../macssubs.html

 

I've taken the test online and it's a no brainer. 15 bucks and cert is in the mail.

 

What???- mine was $25!!! But then, would you really want someone who couldn't pass it playing around with your a/c system?

 

Fast, read PurpleC4's reply in this post.... http://forums.corvetteforum.com/show...m_id=48&arch=1

 

"The original refrigerant - R12 - is available, about 15 Bucks per 12 oz can at Autozone." That is very CHEAP, the last I saw was $50.00 per can at Carlisle PA.

 

Yes, R12 is about $15 now. This is just a simple supply and demand issue. The cars that require it are hitting the wrecking yards now in record numbers so the demand is falling fast.

At the same time 134 prices are going up. This past year the 134 price was flirting with $10.

With 134 prices going up and 12 prices going down, it makes NO sense to convert an R12 system. R12 will keep you cooler and it will circulate the oil better than if you were to convert to 134 and change the oil type. You give up about 15 to 20% of your cooling capacity when going to 134 AND more importantly, statistics show that these conversions last an average of two years before giving any trouble.

I have done lots of a/c work over the years. In fact, I was first exposed to it when my Dad started doing it in his commercial garage in 1956. I was probably 12 when I did my first a/c recharge so that was 44 years ago.

I have done lots of conversions that I wish I could take back. I have also seen lots of problems with the alternative or replacement refrigerants. In fact, I call them JUNK refrigerants.

With R12 at $15 a pound or less, IMHO it is completely foolish today, to convert to ANY other refrigerant. If for no other reason, you will spend more on the conversion fittings and oil than the price difference between the two refrigerants.

Good luck,

 

Thanks for the helpful information. Ed