Compressor test

[airemdwn]

I just bought a 91 Blazer the previous owner jumped the pressure switch to run the compressor all the time. The system is totally empty now. I will be doing a 134 retrofit once i flush and find the leak.

How would i go about testing an A.C. Compressor to see if its dead or not, It spins now easily and doesnt make funny noise when the truck is running.

 

[Fordum]

You can't really test it until you get some gas in and compare pressures from the high side to the low side.
But, if it has been running with no gas for a while, there is no telling what kind of shape its in.
The Freon carries droplets of oil with it as it goes around, and on most compressors, this is what keeps it oiled.
Some of the older ones had oil pans like an engine, but I doubt yours does.

If its been running a long time with the system open, you might want to price a rebuilt unit just so you will know what it will cost just in case.


J.

 

[fallout232]

If you can spin it by hand easily the seals are probably blown in the compressor.

A good indicator if your compressor is shot is pull the orfice tube out. it is screened and will usually catch the seals (sometimes large chunks of them). You can get to it by removing the lower line to the evaporator coil (the lower line on a/c box located on your firewall). Make sure you flush your system good if you find anything.