Topic: 73 Cobra Jet Convertible AC questions

[67foxgt390]

 Hello Every one. Happy to be talking with such a great group. I'm working on my recently acquired 73 CJ conv. While testing some things I noticed that my AC does not blow cold but does seem to "work" I noticed that the heater hoses are not on the car " bypassed I guess" My question is will this prevent my AC from functioning properly? Looks like it might be a pain to replace! Any opinions on this would be appreciated. One more thing, Where are the oil pressure sending unit and the temp sending unit located? I never owned a 351 car! Of course i could find them on my old 390!! Thanks in advance!!  Chuck

[67gta289]

The only ways for the heater to affect vent discharge temp when AC is operating that I can think of are:
(1) AC not set to max cool, and some of the heat from the heater coil is blended in, which would be normal
(2) AC set to max cool, but something with the heater shut off valve or valve control circuit has malfunctioned

But since it sounds like the heater core is bypassed, none of that would be relevant.  An A/C system is fairly complicated and much of it requires special tools and training.  If it gets cold, but not cold enough, you might get lucky and are just low on refrigerant. 

Regarding the sending units, I had to look this up, so no guarantees.

Temp - located below the thermostat. See pic.
Oil Press - located behind the intake manifold.

[J_Speegle]

Temp - located below the thermostat. See pic.

Think you will find that the water temp is (in the picture) above and to the left attached to the front of the block. What you have circled is what is left of the PVS / Ported Vacuum Switch if I recall correctly. Too much stuff in the way on a fully assembled and installed engine

[rickmustang]

Check if you have Freon pressure in the AC system first. If not, you have a decision to make about R134 as the original was R12 stuff but is hard to find and probably illegal. Compressor, clutch and expansion valve could all be issues.

[cobrajet_carl]

Hello Every one. Happy to be talking with such a great group. I'm working on my recently acquired 73 CJ conv. While testing some things I noticed that my AC does not blow cold but does seem to "work" I noticed that the heater hoses are not on the car " bypassed I guess" My question is will this prevent my AC from functioning properly? Looks like it might be a pain to replace! Any opinions on this would be appreciated. One more thing, Where are the oil pressure sending unit and the temp sending unit located? I never owned a 351 car! Of course i could find them on my old 390!! Thanks in advance!!  Chuck

I had a 73 convertible that blew cool but not cold. Gauge readings were OK but compressor cycled on and off a lot. Turns out the de-icing sensor in the evaporator was turning the compressor off at about 50 degrees instead of the 35 or so that it should have been.

[cobrajet_carl]

I meant to add that if you pull the glove box down the connector to the de-icing sensor is right there. You can jumper it pretty easily.