A/C Question !!!
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 5,722
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A/C Question !!!
I have an 82 Crossfire. The AC lines look brand new. Evidently the car has been converted to R134a because I have a the red and blue (high/low) connectors that match up to an R134 charger kit. My freon level is fine, but the A/C is not cooling as much as it should. It's cool at best when the car is moving, and when I stop at a light it gets almost warm again. I completely drained the freon that was in it, ran 2 oz of A/C oil thru it, followed by almost 2 cans of 134a. I checked the psi with the meter, and it's right at the top of the recommended range (45 psi). The compressor is staying on like it should, but it's still not cooling right. I don't have any leaks, because the pressure is
being maintained. I filled thru the low side correctly. Any tips on what's happening here?
Thanks!
Safety Car
Joined: Apr 2002
Posts: 3,551
Likes: 0
From: No link, No dupe
Re: A/C Question !!! (Jman)
I'm not much of an AC man, (usually have the tops off), but I have read that to begin with, the earlier corvette systems did not cool too well. I also think that the problem is made worse using 134a. People have told me that 134A is not as good at cooling, but when used in modern designed cars it is not noticeable. To get really cool air, a complete system from Vintage Air or someone else may be in order, however it is an expensive solution. Again, all of this is stuff I have read or heard, so maybe someone else with experience can suggest something.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
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From: Orlando Floriduh
Re: A/C Question !!! (shotgun_000)
Low side needs to be about 26-28 psi with the engine running at 2,000 rpm. Higher pressure makes it warmer, not colder. My stock 69 system cools great even in 95deg florida heat.. I'm running R134a. No problem.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: A/C Question !!! (Jman)
Jman, you need to a search here on this site for a/c probloems in a C3 vette, the answers are plenty and well published....
for starters....
full fan voltage across fan motor directly when on high speed,
clean the leaves out of the evap housing....
block off the outside air door, remove inside flapper door....puts it in permanent recirculate...
charge to the recommended 80% of R134, check for leaks of course...
seal off all firewall leaks, insulate under the carpeting...
insulate under/over the tranny tunnel, seal any shifter boots well...
make sure the fans draw plenty of air through the a/c condensor and radiator...in other words WORK.....
GENE
for starters....
full fan voltage across fan motor directly when on high speed,
clean the leaves out of the evap housing....
block off the outside air door, remove inside flapper door....puts it in permanent recirculate...
charge to the recommended 80% of R134, check for leaks of course...
seal off all firewall leaks, insulate under the carpeting...
insulate under/over the tranny tunnel, seal any shifter boots well...
make sure the fans draw plenty of air through the a/c condensor and radiator...in other words WORK.....
GENE
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: A/C Question !!! (mrvette)
I agree with Gene. These cars CAN be hot boxes if everthing isn't just right. I really think R134a has gotten a bad rap due to overcharging for one thing. It doesn't transfer heat quite as well as R12 so the condenser needs to be clean and in good shape(no debris or flattened fin areas). Make sure the aux fan is working also. My 69 Big Block (No aux fan like later years.) will get almost too cold on the road and stays cool enough in traffic, even when the engine gets to 210deg. :cool:
[Modified by silvervetteman, 4:49 AM 5/13/2002]
[Modified by silvervetteman, 4:49 AM 5/13/2002]
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
Re: A/C Question !!! (mrvette)
I believe mrvette hit it on the head. Order a book from one of the many Vette part suppliers, titled something like "AC stratagies for the 68-82 Corvette". It's a good book and it will elaborate on everything mrvette stated above. My system will be coming apart in the next couple of months . . . gotta have AC in TX!
Please follow up on this if you figure it out and tell us what you did.
Please follow up on this if you figure it out and tell us what you did.
Burning Brakes
Joined: Oct 2001
Posts: 860
Likes: 40
From: Woodforest
Re: A/C Question !!! (Jman)
Agree with all the above, most of your problem seems to be in overcharging. Check that your electric fan is working as well. It should kick in immediately when you turn on the A/C. In addition, you might want to check your evaporator. After 20 years, it will need a good cleaning to transfer heat properly. You may want to install a valve in your heater coolant line as well. If the selonoid is not closing properly, you will be leaking by coolant into the heater core, reducing the efficiency of the system. A manual valve can eliminate that possiblity and its inexpensive.
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Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
Re: A/C Question !!! (Woodstoc)
Another thing is that there seems to be something wrong with the system... You said "almost 2 cans" brought the low side up to 45 PSI. This is undercharged, yet your low side is already high. The C3 takes about 3 cans of R134a, and the low side should work its way down to 25 PSI, cycle off and go to 45, and then cycle down to 25 etc. If it never gets below 45 PSI with such a low charge, something is blocked.
A professional flush might be a good idea.
BTW, my '71 cranks out 42F vent temp on a 90F day with R134a. They will definetely cool well when everything works.
A professional flush might be a good idea.
BTW, my '71 cranks out 42F vent temp on a 90F day with R134a. They will definetely cool well when everything works.
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Re: A/C Question !!! (Jman)
The fact that it cools better when it has airflow over the condenser tells me you need to improve this at idle, I assume with an auxiliary fan, but it may also be a problem with something else as indicated in the previous posts. In our fleet, we have converted a bunch of cars and trucks, and most systems work BETTER on R-134a! My own personal '92 Suburban is 4 degrees colder with it.
Hans
Hans