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C3 Air Conditioning Problem

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Old Sep 8, 2015 | 05:01 PM
  #21  
bill1973's Avatar
bill1973
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Joined: Sep 2015
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Default 1973 Air conditioner not working properly

Originally Posted by redwingvette
If your system still has a VIR valve then that may be the issue. They are setup for R12 and may need to be reworked for R134.
I completely replaced my system last spring.
I have a few problems with my AC and was wondering if someone could offer help for this R12 system


Problems:
1. AC cools to ~52degreesF. However, Fuse link for low pressure keeps blowing.
2. High side operating pressure is too low.
3. Frost is on line going into evaporator in dash.
4. Highest setting of fan does not work.


What I have done:
  • Had the VIR valve rebuilt.
  • Flushed the hoses and condenser
  • Replaced seals on VIR and compressor
  • Static reading is 75PS for both Hi and Low, no leaks
  • Clutch engages when I manually jump fuse link. no issues
  • Running/engaged pressures are 50 PSi and 120 PSi in 100degree F heat (Arizona). High should be about 240.
Do I need a new compressor?
  • If my car is mostly original, I want to keep it original. If it is not original, I want to replace it with new.
  • How do I tell if the compressor is original?
thx
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Old Sep 8, 2015 | 07:30 PM
  #22  
70ZZ3 96LT4's Avatar
70ZZ3 96LT4
Burning Brakes
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Joined: Oct 2001
Posts: 911
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From: TN
Default desiccant

The only time my 45 year old 1970's factory air conditioning would not cool was because the desiccant broke loose from inside the receiver/drier and clogged the screen in the valve that the condenser line connects to feed R12 to the evaporator. This is a very small screen and if clogged the R12 or R134 is not going to get to the evaporator. Cleaned the pathway for the R12 from the receiver/dryer through the condenser to the valve, replaced the small screen since it was so inexpensive, pulled vacuum, installed R12, and installed a new receiver/dryer and it had cold air again.

Last edited by 70ZZ3 96LT4; Sep 8, 2015 at 07:36 PM.
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