C2 Factory A/C Question

**Dennis Rosenthal** · September 15, 2004, 05:29 PM

Re: C2 Factory A/C Question

Bruce, STV is an easy rebuild, long island corvettes sells the kit. First I would check your freon level, if it is low the AC will act as you describe. as for a retro update kit, POA valves are discontinued at most suppliers. There is an update kit available that uses a valve with a low pressure switch. Easy to install, I have had nothing but success with them. Dennis

**mike geary** · September 15, 2004, 05:35 PM

Re: C2 Factory A/C Question

Bruce: ain't it great being a C60 owner? Even though you seem to be seeing R12 "flow" in the sight glass, I'd suspect the expansion valve if you're not getting any cooling of the evaporator input pipe. Seems to me that any flow of freon through the exp. valve should result in some "coolness".

Have you checked the A/C section in the 1965 Supplement? It's pretty good and I seem to recall a troubleshooting table.

If it turns out to be the STV, it is easily rebuildable with a new piston/diaphragm, which I obtained from the good folks at LICS. The 65 supplement contains the procedure. Watch out for that big internal spring; it's under a lot of compression. Also suggest scribing the two housing sections before separating them to help in reassembly.

Good luck and let us know what it turned out to be. I'm sure we'll be able to put the info to good use.

MAG

**Allan Wicklund** · September 15, 2004, 08:40 PM

Re: C2 Factory A/C Question

Hello All! Somewhere along the last few weeks there is a posting in response to my STV/POA question stating that the pressure setting on the LOW side of the STV must be correct or a "No cool" situation arises. FWIW. Al W. (I'm currently converting my system from STV to POA to correct the wrong STV in my 67 as it should be a POA.)

**Bruce Boatner** · September 16, 2004, 09:28 AM

Re: C2 Factory A/C Question

Mike,

With the temperature in the mid 90's lately and with the high humidity here in Houston, being C60 owner has been really great, especially since I use my car as a daily driver. Needless to say, my dry cleaning bills are spiking lately.

My car is a 1964 and I did check out the A/C section in the supplement. You're right, it really is good. If it weren't for the supplement, I would not have had the foggiest idea of even where to look.

I really hope the expansion valve is the culprit because it looks like it would be much easier to replace as well as much cheaper than the STV.

Is it relatively easy to isolate the problem to either the STV or expansion valve if one has the proper gauges? I think you can rent these at the auto parts store if I'm not mistaken. I have never fooled with testing A/C systems using A/C gauges before, but it does not seem to be rocket science. Is this something a shade tree mechanic should take on?

I realize I will take the car to a shop eventually to have the system recharged with R12 (unless someone convinces me to convert to R134--thoughts?). I would much prefer to have a good idea of the exact problem is before I go to a shop rather than be at the mercy of someone else and chance getting ripped off.

Thanks for your help!

Bruce

**mike geary** · September 16, 2004, 10:19 AM

Re: C2 Factory A/C Question

Bruce: Yes, definitely pick yourself up a set of gages (often on eBay) and do a little studying on how to troubleshoot your system. It is not the black magic that it seems to the neophyte.

As a C60 owner, I recommend acquiring a '70's vintage how-to book on A/C diagnostics and repair. With that knowledge, a vacuum pump (also a good eBay candidate), and a set of gages (get the long 72" hoses for convenience) -- you will be well on your way to self-sufficiency. Except for the R-12 of course.

For that, you can get your certification by passing an on-line, open-book test. Then you can get all the R12 you need off of eBay for less than $20 a can.

Mike

**Jim T.** · September 16, 2004, 10:23 AM

Re: C2 Factory A/C Question

Bruce you many not need to replace the expansion valve. On page 13-15 in your 64 Corvette supplement is a picture of your expansion valve. The liquid R12 comes from the dryer to the expansion valve and must pass through the small inline metal filter seen at the inlet to the expansion valve. What may of happened with your system is that the bag that contains the desiccant could have ruptured and migrated from the dryer to the expansion valves cone syle metal filter. I know from experience on this problem. All you have to do is recover the R12 in the system and disconnect inlet line to the expansion valve to check the filter. I used a easy out to grasp the small metal filter to remvove it. I was able to just buy a new one, flush out the line from the dryer to the expansion valve, replace the dryer, vacuum the system down, and recharge with R12.

**Bruce Boatner** · September 16, 2004, 12:37 PM

Re: C2 Factory A/C Question

Mike,

Where should I look to find the on-line, open-book R-12 test? Sounds like a great idea!

Acquiring R-12 was my biggest stumbling block to avoiding a shop (well, ignorance is also a big factor). I'm sure I could easily recoup an investment in gauges and vacuum pump through labor savings.

Bruce

**Bruce Boatner** · September 16, 2004, 12:41 PM

Re: C2 Factory A/C Question

Jim,

Thanks for the tip. I will definitely check out the expansion valve filter.

You mentioned that I should "recover the R12 in the system". How is this accomplished? Is it possible to restore the R12 in the system after recovery?

Thanks!

Bruce

**Jim T.** · September 16, 2004, 02:50 PM

Re: C2 Factory A/C Question

Bruce if you are going to try and do the work yourself you will have to find a air conditioner repair station that will remove the R12 from your system and agree after you do the repair to vacuum the system down and reinstall it and only charge for the labor and any additional R12. Finding a shop that will work with you on this is the only way I know to recover the R12 since you don't have the equipment. A competent shop will also know how much compressor oil to the system. Having the correct amount of oil is important after purging the system of R12 and replacing the dryer. If your front seal is leaking in the compressor this would be a good time to have the updated better sealing ceramic seal that GM sells installed.

**mike geary** · September 16, 2004, 05:21 PM

Re: C2 Factory A/C Question

Bruce: Try Googling "ASE Refrigerant Recovery & Recycling Quiz".

Or go to http://www.asecert.org/subchannels/p...rant_online.cf

The fee was $15 in 2002 when I completed the course.

Mike

C2 Factory A/C Question

C2 Factory A/C Question

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