Need some help. My '63 Galaxie has factory A/C that worked when I bought the car. Though, you had to get up to higher rpms for it to blow cold, it worked. Now, nothing. The compressor kicks on and stays on, and I know there is coolant in the lines. The thing holds compression. But, no cold air. The previous owner over-charged the system, but would that cause it to not work? What can a guy do? Thanks for any help.
Several questions enter my mind when thinking about this. Has the system been converted to R134A? You say "the thing holds compression"....what does that actually mean? You need to get pressure readings from both the low and the high side of the system, and if you aren't sure how to do that, it's best left to a professional or someone that is familiar with a/c systems. A guy that isn't well versed in these systems can end up really hurt if something were to go wrong.
I will elaborate further...Just because there is pressure in the lines means nothing. There has to be a "differential" in the pressure between the low and the high sides of the system if the compressor clutch is engaged. Without having pressure readings from both sides, you will be shooting from the hip so to speak, on the diagnosis. The first piece of information you need are the pressure readings before going any further, if indeed the clutch on the compressor is engaging. BE SURE TO WEAR SAFETY GLASSES if you are going to attempt to get the pressure readings yourself. BTW, if the system was overcharged, and someone just "bled" it out, then they broke federal laws.....not that "I" have EVER done that!
Sorry for not being more specific. Yes, it's been converted to 134A. I was informed that if there wasn't pressure in the line, the compressor wouldn't stay on...or something like that. (whoops) I'll get on getting a pressure reading. I won't attempt it myself, I've heard horror stories. But I would like to gather as much information as I could. Thanks.
That is only true if: -the low pressure switch has not been bypassed..or.. -the low pressure switch is working correctly The low pressure switch, when working properly, will disable the compressor clutch if the system pressure gets too low, due to leaks. If it is still working, but the system pressure is high enough to keep the switch on, the pressure could still be far too low to cool....meaning it could need a recharge. And that is why gauges are a must.
^^^ What F&J said. The low pressure switch just insures that the compressor won't be damaged due to lack of refrigerant in the system. Knowing the pressures on BOTH sides while the compressor clutch is engaged is key to properly diagnosing.
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