What about an old A/C?

[Pauk]

So I picked up a sweet 1973 LeMans last year with only 23,000 miles on the clock.  One of only things not working is the A/C.  I wonder if anyone out there knows what needs to be done to an old A/C system.  When took mine in to the local GM shop, they got it sort of half working - putting out cool air, not cold.  The mechanic evidently said one of the tubes was freezing up and I'd need a new Thermal Expansion Valve.  So I got one and took it back, but evidently he then said he'd need the circuit breaker that goes with it, (I've looked around and see nothing about circuit breakers being available).  There was also talk about having to do a conversion from R12 to R134 and someone told me that could cost me Cdn$4,000-5,000 (I live in Canada).  Yes, you're right, I'm not getting a lot of help out of GM mostly because I have only been able to talk to the dealer service representative and not directly to the mechanic.  Which is why I'm here on Forever Pontiac!  Anyone want to suggest what they would do if they found themselves in my situation?  Thanksabunch.  

[Frosty]

Find yourself an A/C speciality shop and cut out the middle man and talk to someone who truly knows what they are doing. Since the 68-72 Lemans/Tempest/GTOs are so popular with the aftermarket, a lot of these A/C parts are reproduced. Many of these parts should work on your Colonnade style '73 Lemans. A company called Classic Auto Air advertises that they have original A/C parts. You might try contacting them for the parts you need.  www.coolmyhotcar.com   1-866-390-7676

Conversion from R12 to R134 is a personal choice, in my opinion. Now, not knowing what Canadian law states on this sort of thing, I am shooting from the hip. However, R12 is bad for the ozone long term but you can still get it, but it is not cheap anymore (around $35 per 12 oz can and up on eBay). R134a is now the refrigerant gas of choice. So if your system is already empty, it may be cheaper to fill it with R134a.

BTW - my first Pontiac was a '73 Lemans Sport Coupe. Be sure to post some pictures of your ride when you get a chance.

Edited April 4, 2017 by Frosty

[Pauk]

Geez it's nice to run into someone who knows what they're talking about.  Thanks, Frosty.  Does converting from R12 to R134 necessitate replacing the whole shebang, as in compressor, condenser, pipes and hoses?  Or maybe just the seals, I've heard?  Or can you just take the R12 out (disposing of it properly of course), and put in R134 and have it all work?  I know, the A/C specialty shop will know, but I'm curious and I've 'got you here.'

Edited April 4, 2017 by Pauk

[Professur]

http://www.aa1car.com/library/retrofit.htm

 

This pretty much covers it, with no half assing involved.

[Pauk]

You said it.  Perfect.  Many thanks.

 

G

[Frosty]

Honestly, as Pro's article states, it depends on the state of your system. I'd rather have the A/C shop tell me what I need. They might even be able to order the necessary parts.

[Professur]

Here's the thing ... all these recharge kits miss one big point. Before you charge the system, you want to test it for leaks under pressure. Then you need to draw it down to vacuum. Only then do you add the oil and Freon charge. If you don't, a portion of the volume will be useless damp air. Now not every shop is going to be ready to handle an old car conversion, even if they claim the expertise. And even a quality shop will have it's share of wrench apes and counter monkeys. You're best off not volunteering an opinion. If you don't tell them what you know, if they try to sell you blinker fluid, you know to keep shopping. Letting them know you're not a mark might have them singing the right song, but still half assing the job.

[Frosty]

17 hours ago, Pauk said:

Geez it's nice to run into someone who knows what they're talking about.  Thanks, Frosty.  Does converting from R12 to R134 necessitate replacing the whole shebang, as in compressor, condenser, pipes and hoses?  Or maybe just the seals, I've heard?  Or can you just take the R12 out (disposing of it properly of course), and put in R134 and have it all work?  I know, the A/C specialty shop will know, but I'm curious and I've 'got you here.'

Typically once a system has been opened, it is common practice to replace the drier/accumulator with a fresh one. Fresh new seals are a good idea to replace the old ones if the are bad, or at the very least, A/C lubricate should be added to an empty system to help re-seal them from the inside. A compressor can go bad from use or just sitting, so it should be tested and replaced if necessary. Everything else should be okay for the most part unless there is some other corrosion or damage to the system.

[Pauk]

Thanks, all, on this.  One more question.  IS there actually a circuit breaker associated with this A/C Thermal Expansion Valve?  I've searched online and don't see it even listed, much less available.

Gary

[Frosty]

5 hours ago, Pauk said:

Thanks, all, on this.  One more question.  IS there actually a circuit breaker associated with this A/C Thermal Expansion Valve?  I've searched online and don't see it even listed, much less available.

Gary

There is no circuit breaker that I am aware of for the thermal expansion valve.  To the best of my knowledge this is fair mechanical in nature and it either works or it doesn't. I suppose it is possible for it to have a sensor but no switch.

There is a switch on the compressor but I think you already knew that.