Join Date: Sep 2013
Location: West Des Moines, IA
Re: 68 Camaro underdash ac /heater box
What are your suction and high head pressures? Your suction (or low side pressure) should be at around 36 psi. Your high head will vary more based on outside air temperature, but around 180 psi. With only two cans of R-12, there isn't enough freon to fill your evaporator (hence the cold and hot). You may also have a POA valve not functioning correctly. Also the sensing bulb must be totally secured to the suction line and (immediately where it exits the evaporator case) totally covered with insulation. If any engine compartment heat can get to the sensing bulb, it will not tell the suction throttling valve to do its job. Let me know what you find!
'67 RS, convertible, factory A/C, 327/275 (M30), powerglide, parchment interior