Air Conditioning Help

[Saltydog]

I have a 82 vette.
I replaced the AC compressor, drier, orifice tube, and had a local Firestone shop to charge my system with 134a. I have determined that my air box doors are all functioning properly including the max air outside door. I have placed a cutoff valve on my heater core hose and shutoff water flow to it.
The AC when placed in Max cool with car running at 55 mph on highway will blow at vent a temperature of 48 degrees, which is ok with me, but when I stop a idle the temperature will increase to 60 degrees. My 88 silverado pickup with 134a gas will put out 40 degrees at vent temp when it is idling.
I am now wondering if placing some sort of relay switch to turn on the electrical radiator fan will help with my problem. It seems as though I need more airflow across the coil as happens when I am traveling at 55 mph.
If some one knows the proceedure for electrically hooking up such a relayed switch please advise me. 10 to 15 degree vent air temps are to much.
Thanks for any help.
Saltydog

 

[joe1975]

I put A/c unit in a jeep using 134 $1400 set up left a lot to be desired alot of cars I've seen using the 134 don't cool that good not even think about at idle

 

[drags1998]

Saltydog, have a radiator shop check for the correct charge in the A/C system!!!! You should be able to get 38-40 degree air out of the vents sitting still. DONT blame R134 for the problem,I think youll find the problem when the low side pressure is checked.

 

[Saltydog]

Hello Drags1998 and joe1975

I had my local Firestone shop vacumn down the system and install the correct amount of 134a. Pressure on the low side is with in the good pressure range at 35. Idle wont allow the low temp cooling to happen. The mechanic there suggested that I rig my stock aux electric fan to come on when I turned on my AC so a greater Heat exchange would happen. He said that If i did this that I would notice better cabin temps. I had heard of other vet owners doing this. I was hoping some one would read this thread and tell me exactly how then worked a relayed switch to the AC on Switch. And tell me how well it worked.
Any comments will be welcome
Thanks Saltydog
Drags 1998. Will a radiator shop do better than a Firestone shop ??

 

[photovette]

Here's my system; the AUX fan only runs when:
a. Coolant temp exceeds 200F
b. Manual switch is on.
c. A/C compressor clutch is energized and the brake pedal is depressed.
This endures that the AUX fan only comes on when the car is stopped or
in stop and go traffic.

 

[joe1975]

My experience with 134 in my jeep wrangler left a lot to be desired had an aux fan installed didn't help a lot at idle

 

[photovette]

The AUX fan on '79 through 1982 'vettes is a high volume, well designed fan. I added it to my '77 with great success.

 

[joe1975]

Thats a push aux thru the rad.

 

[drags1998]

saltydog, I didnt mean to imply that the firestone store couldnt handle the job!!!!!! Its just in my area, the rad. shops work on heating,A/C and gas tanks, THATS IT!!!!!! Take a good look at the wiringdiagram posted here, it looks like it would work GREAT!!! Not sure you need the brake switch in there, but either way try it and let us know!!!!!!

 

[Bob Chadwick]

I have a 77 that I converted to R134. Works great at speed, well except for the low volume of air produced by the HVAC fan but that is another issue, getting the air to about 38 degrees. When I get in stop and go traffic for an extended length of time, the temp starts to approach 60.

I've thought about adding an aftermarket aux fan for traffic but have decided if I am going to go that route, I'm just going to pull the whole shroud, clutch, mechanical fan, etc. and add one of the high performance electric fans cleaning up the front of the engine and adding space.

 

[Lee74C3]

I have a 1974 Coupe with a 454... you want to talk anout hot! I have driven many 1982's withou a problem. Something is wrong on your car and all the aux fans in the world won't fix it.

I have always found that the factory installation (with R12 or R134A) will always perform beyond normal expectations. This is contingent on everything working the way it should and all parts in place. This includes fan shrouds, hood seals, etc.

I think you need to find someone else to service your AC.

 

[Saltydog]

Thanks Guys for all the suggestions. I'm gonna try them all. I will tell you all that I
added 12 more oz. of 134 than the shop put in it ran the car down the road. The vent temps took longer to drop to 60 degrees so I came back and reduced the amount in the system to an amount that brought the low pressure side down to 45 pounds. I drove out on the highway and low in behold my vent temps dropped to 48 degrees when I put the blower fan on medium blow the temp dropped to 42 degrees I was supprised and pleased. At this point I feel as though I need to hook up a switch to cut on my aux. electric fan when I turn in my A/C. The reduction in the 3 pounds the shop put in seems to have made a difference. If at idle, in downtown traffic, the car would preform at those temps that would be great, but I have yet to prove that. Well, Thanks guys for any other comments or suggestion, I am headed out to try to work on it some more.
Thanks Saltdog