Test for Evaporator and Condenser Coils

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charliec

charliec

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My '68 Dart has factory AC. It was not functional when I bought the car, but I don't know if it didn't work or PO just wanted to remove the power robber. The car was apparently raced. All the underhood apparatus was missing. I bought a used compressor and condensor, dryer, etc. from a yard. The evaporator coil is still in the heater/AC box. All of these components have sat in the shop for 20 years or more. I think I can piece together all the necessary components, but the question is: How do I know if any of the components are good without putting the whole dang thing together? Are there effective bench tests for any of this stuff?
 
From what I know, (not a great deal about AC) from watching tests , you have to pressurize the components with a colored dye poured in. Wherever the dye leaks out, indicates the leak source. If you can find some way of pressurizing each component ,maybe with compressed air, you may be able to establish if each component is leak free.
You should be able to power up the compressor with a 12 volt source. It is basically an air pump so you should feel air coming from the outlet fitting. Also, I think there is also a clutch that could be activated by a 12 volts source to check it.
 
Or use a vacuum pump. For both compressed air or vacuum you may have to make up fittings with hose and shut off valves.
 
I used to take parts like evaporator coils and pressurize them with compressed air and dunk them in a bucket of water. You will find leaks easily. Can take some improvising to seal up the fittings…..
 
Yup. Biggest issue on some parts is getting fittings that you can hook them up and seal them.

Vacuum does not work all that well to actually find leaks. There are "detectors" that are supposed to find vacuum leaks, but a guy wonders just how effective they are.

One effective tool is the old school "halide torch" which is a propane torch with a draft tube rigged to it and a small piece of copper in the flame. It lights up blue - green with R12/ R22. If you can get a small amount of R12, evacuate the complete system, put in some R12, add more pressure with R22 if you have it, and then pump it up with CO2 or N2 to about 200 PSI and go to work with the halide torch. If it leaks "really bad," move to CO2 or N2 and soap bubbles
 
67Dart273 said:
Yup. Biggest issue on some parts is getting fittings that you can hook them up and seal them.

Vacuum does not work all that well to actually find leaks. There are "detectors" that are supposed to find vacuum leaks, but a guy wonders just how effective they are.
Click to expand...

Agreed. I've pulled systems to 30inHg and let set for 10-15 with no drop in vacuum, only to have a leak somewhere.
 
The corrosion on a 20 year open system would be a big concern for me.
 
The problem with vacuum is, that it is only equivalent to roughly 14-15psi test pressure, and even turned off, the system sees way more pressure in static refrigerant pressure.
 
I think my best bet is to have a radiator shop check it out. The system has been sitting for a while and is in many pieces, so a freon leak detector is way premature
..no freon or pressure in the system. I will flush the crap out of the coils first and then have the radiator shop pressure tjem up and dunk them. They can put plenty of pressure on them.
 
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