AC Problem... - RX7Club.com - Mazda RX7 Forum

3rd Gen General Discussion The place for non-technical discussion about 3rd Gen RX-7s or if there's no better place for your topic

AC Problem...

Old 02-18-19, 08:48 PM
  #1  
Full Member
Thread Starter
 
Join Date: Apr 2018
Location: NC
Posts: 107
Thanked 1 Time in 1 Post
AC Problem...

The AC on my car doesnít work and I donít know if it ever worked for the previous owner. I noticed that when I turn the AC on, the AC sensor on my Power Commander controller doesnít light up. I read a bunch of threads that said I need to possibly wire a relay to the Power Commander. The compressor clutch doesnít engage but the AC relay does ďclickĒ when I press the AC button. It occurred to me that perhaps my system isnít charged and the pressure switch may be preventing the compressor from turning on.

When I had my engine rebuilt by Rotorsports Racing, they replaced my compressor, which was very rusted, with a used one. By their own admission, they arenít AC guys, and while I donít know AC, my research says that when you replace the compressor, you have to discharge the system. Either they did it or there was nothing left in the system (I need to call them).

So...that brings me to this: what do I do about the Freon? R12 from what I found is hard to get, if at all. How hard is it to convert to whatever r134a? Is that my only option at this point?
Djseto is offline  
Old 02-19-19, 07:46 AM
  #2  
RX-7 Bad Ass
iTrader: (52)
 
DaleClark's Avatar
 
Join Date: Jan 2002
Location: Pensacola, FL
Posts: 11,066
Thanked 244 Times in 209 Posts
If they replaced the compressor, they would have had to evacuate the refrigerant from the system. If it was bad, most likely the system was totally empty and everything had leaked out.

Lots of guys have been using R-152a, also known as Dust-Off, for the AC system. As in the cans of compressed "air" to blow out a computer keyboard or whatever. Do some searching on it, there's a HUGE thread in the 2nd gen section on this topic. Most shops won't do 152a, this is typically something you have to do yourself.

You can go 134a but the car will never cool that well. R12 in an FD works AMAZING and it is still possible to buy it on Ebay but you typically have to have an HVAC cert to be able to buy it. I did a test online ages ago to get my certification, it's doable and not that hard to get the cert. I did it on a slow day at work once .

Dale
DaleClark is offline  
Old 02-20-19, 12:53 PM
  #3  
TANSTAFL
iTrader: (10)
 
alexdimen's Avatar
 
Join Date: Oct 2003
Location: Richmond, Va.
Posts: 3,366
Thanked 30 Times in 23 Posts
Do you plan to charge yourself or take it to a shop?

If you're intent on DIY there is also Envirosafe ES-12 at autorefrigerants.com

ES-12 is a propane/isobutane blend. I've been using it in my E28 and 93 Rx-7 for years now. Works reasonably well. I could never keep 134 in my system for very long due to the smaller 134 molecules leaking out of the R-12 system.

Your best bet is go to a real AC shop that hopefully still has R-12 in their tanks and a good machine to pull a hard vac and charge by weight. Have them replace your schrader valves and o-rings while you're at it. A new dryer isn't a bad idea either as it absorbs moisture over time, especially if the system was exposed to outside air.
alexdimen is offline  
Old 02-20-19, 01:18 PM
  #4  
Full Member
Thread Starter
 
Join Date: Apr 2018
Location: NC
Posts: 107
Thanked 1 Time in 1 Post
Originally Posted by alexdimen View Post
Do you plan to charge yourself or take it to a shop?

If you're intent on DIY there is also Envirosafe ES-12 at autorefrigerants.com

ES-12 is a propane/isobutane blend. I've been using it in my E28 and 93 Rx-7 for years now. Works reasonably well. I could never keep 134 in my system for very long due to the smaller 134 molecules leaking out of the R-12 system.

Your best bet is go to a real AC shop that hopefully still has R-12 in their tanks and a good machine to pull a hard vac and charge by weight. Have them replace your schrader valves and o-rings while you're at it. A new dryer isn't a bad idea either as it absorbs moisture over time, especially if the system was exposed to outside air.
If it's an easy DYI, I'd do it but I'm not opposed to paying a pro to do it either. With 124 or ES-12, would I need to get a new compressor or would it shorten the life of my compressor?
Djseto is offline  
Old 02-21-19, 09:01 AM
  #5  
TANSTAFL
iTrader: (10)
 
alexdimen's Avatar
 
Join Date: Oct 2003
Location: Richmond, Va.
Posts: 3,366
Thanked 30 Times in 23 Posts
Originally Posted by Djseto View Post
If it's an easy DYI, I'd do it but I'm not opposed to paying a pro to do it either. With 124 or ES-12, would I need to get a new compressor or would it shorten the life of my compressor?
I wouldn't call proper AC work an easy DIY. I used to do it professionally and it's so much easier with a proper AC service machine with quality fittings. You need a manifold set and a good electric vacuum pump at the very least. Even then you are charging by volume and pressures and not weight unless you get a scale. Not a problem, but I would always prefer to use a scale.

ES-12 can be used with R-12 compressors and standard R-12 mineral oil which makes it an ideal substitute. There are a number of threads on it around here. I would pull a hard vac, break the vac using ES-12, then charge as recommended. Many people just use 2 cans of it IIRC.

I think there are some issues with mineral oil and 134. Best practice is to drain the compressor, get a new dryer and add PAG oil for 134 conversion. Side note - I hate 134 conversion adapters, hard to find good ones and they always seem to leak a little. One more failure point.

Best bet is to do the job right with R12 professionally - replace dryer, easy to reach o-rings, and schrader valves. That way your precious new charge of R-12 doesn't leak out and blow a hole in the ozone layer.

Last edited by alexdimen; 02-21-19 at 09:04 AM.
alexdimen is offline  
Old 02-21-19, 03:48 PM
  #6  
Full Member
Thread Starter
 
Join Date: Apr 2018
Location: NC
Posts: 107
Thanked 1 Time in 1 Post
So I called a local AC shop and they said R134 is the only legal option they can do. They said R12 is almost impossible to get and expensive and he had no idea was ES-12 was except to say there are some "black market" things out there but the only legal sub he can do is R134.
Djseto is offline  
Old 02-22-19, 06:48 AM
  #7  
Fight the Cancer
iTrader: (42)
 
Molotovman's Avatar
 
Join Date: Jul 2002
Location: Northern Virginia
Posts: 3,289
Thanked 44 Times in 39 Posts
Originally Posted by Djseto View Post
So I called a local AC shop and they said R134 is the only legal option they can do. They said R12 is almost impossible to get and expensive and he had no idea was ES-12 was except to say there are some "black market" things out there but the only legal sub he can do is R134.
If you want to use a different refrigerant just ask them flush the system, replace the refrigerant oil with an oil that will work for the refrigerant you want to use and have them pull a vacuum on it. Get it back under vacuum and then charge it yourself.
Molotovman is offline  
Old 02-22-19, 08:24 AM
  #8  
38 years of 7's
iTrader: (1)
 
mikejokich's Avatar
 
Join Date: Jan 2012
Location: Alabama
Posts: 260
Thanked 33 Times in 32 Posts
R12 is the way to go if you can find someone who can do it. I had my car recharged with R12 after my last rebuild and it is "as cold as ice", just like the old Foreigner song. LOL. I am serious though, call around until you can find someone who has it and can put it in.
Mike
mikejokich is offline  
Old 02-22-19, 09:48 AM
  #9  
TANSTAFL
iTrader: (10)
 
alexdimen's Avatar
 
Join Date: Oct 2003
Location: Richmond, Va.
Posts: 3,366
Thanked 30 Times in 23 Posts
Yeah, call around. It doesn't have to specifically be an AC shop. The full service shop I worked at had a good dual refrigerant AC machine and I bet they still have R12 still in it. Mostly we did 134 conversions but they would charge with R12 if you specifically requested it.

ES-12 is actually better for the environment than the other standard refrigerants out there and isn't regulated so they just don't feel like taking the risk of charging your system with it. It's definitely not illegal.
alexdimen is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
CYM
3rd Generation Specific (1993-2002)
2
04-05-03 01:24 PM
wai
General Rotary Tech Support
2
03-12-03 09:23 PM
trust7
General Rotary Tech Support
8
11-20-01 08:38 PM
trust7
3rd Gen Archives
41
11-07-01 05:48 PM
Ryde _Or_Die
2nd Generation Specific (1986-1992)
23
10-19-01 09:26 AM


Thread Tools
Search this Thread
Quick Reply: AC Problem...


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.