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Everything seems ok, but not very cold

Wajulia on Sun June 16, 2013 10:01 PM User is offline

Year: 1981
Make: Chevy
Model: Corvette
Engine Size: 350
Refrigerant Type: Enviro-safe r12
Ambient Temp: 80
Pressure Low: 25-45
Pressure High: 180-215

1981 corvette - Finally got around to fixing my AC after it has been empty for 27years. I pulled a vacuum on it for about an hour. After 30 minutes it was still holding a vacuum. So I added three 6 oz cans of Enviro- Safe. I decided to use this instead of converting to r134. The instructions say that each can is equivalent to 18 oz of r12

After the first can, the compressor clutch came on ( I admit I was happily surprised). I put in the other two cans, compressor cycled nicely. I used an oil tester and it read low on oil, so I added 3 oz of oil.

Problem, the air from the dash is 60 deg. I am pretty sure the heater is not on, temp from the vent setting is the same temp as outside air

Static pressure on both sides is 80 psi

Operating pressures when cycling
Low side 25-45 psi
High side 180- 215 psi
Ambient temperature is about 80 deg
Low side pipe to the compressor is cold to the touch ( seems much colder than 60 deg)

Seems like the compressor is working correctly. Any ideas why the temperature is so high?

Dougflas on Mon June 17, 2013 5:31 AM User is offline

Could be a problem with interior ducting, blend doors, etc

GM Tech on Mon June 17, 2013 7:25 AM User is offline

It IS a Corvette-- not known for good cooling---styling came first- cooling was an afterthought when designed....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

wptski on Mon June 17, 2013 8:08 AM User is offline

My 1978 Corvette the same C3 class as the OP and stored since 2002. Had the following when charged, at idle, 60F ambient with a fan in front of vehicle. Windows down, max cool and passenger side vent near evaporator was 37.5F. Just put the plates back on and will find out in the next few days if all is well while driven or anything else is wrong. Interior on these are always hot IIRC, heat from transmission area is high as one can feel it on your legs. Engine compartment is hot and touching anything under the hood after driving in summer can be painful including the metal hood prop.

Year: 1978
Make: Chevy
Model: Corvette
Engine Size: 350/5.7L
Refrigerant Type: R12
Ambient Temp: 60F
Pressure Low: 26
Pressure High: 165

Edited: Mon June 17, 2013 at 8:08 AM by wptski

iceman2555 on Mon June 17, 2013 11:31 AM User is offlineView users profile

Put the tops down and let your hair blow in the wind. Vettes were not made to cool....but to look cool. Unfortunately it is difficult to adequately cool the cabins in some of the older units. The new units....wowwww....they are fantastic...good (both in and out)...go like the wind and get good gas mileage. My last big block would not pass a gas station....and required the most expensive fuel available. Made lots of noise (great sounds)....ran like a scalded dog.....leaked water in the rain.....had wind noise at speed.....heck...had wind noise all the time....but dearly loved the beast. Sorry I sold it...not for the sentimental was just a car...but now it would be worth some serious bucks....could buy a new one....great stereo....looks great...gets cold inside....drop the top and let my white hair blow in the breeze.
Next issue....the EnviroSafe carp...but then....that is another issue on it's own and each year it seems to come back. Insure the system is sound and put 12 back in the system. What type lube tested was used? Curious about that one.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

wptski on Mon June 17, 2013 11:54 AM User is offline

No hair left to blow in the wind, only memories of what was there!

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