How do you check AC compressor?

[MICAHMOBERLY]

Yep, my boys 89 has same problem, no AC, but the compressor works, I was told to convert it from old to new only to screw on the new valve onto the old valve, and then you will be able to charge the 134, Is this a good assumption???

[mrnickleye]

You can TEST to see if the clutch is good, and if the compressor is not locked up, by juming 12v to the compressor wire while the engine is running. Just for 10 seconds.

If it seems to work.....

It is possible to buy the fittings and put them on. Just be sure to remove the schrader valves from the original fittings first. You can get one of those cheap R134a install hose kits and a can of it.

You will be hooking the hose to the fitting on the compressor, the 'low side'. With the engine off !!!

This will help you find out if there are any NOTICEABLE leaks.

Look at all the fittings and hoses. Use a mechanics stethoscope with a hose attached to listen for leaks.

Let it sit over night, then, using a pocket screwdriver, press on the schrader valve to see if any freon is still in the system. Yes, pressure, then you could go and have it finished converting at the shop.
No...then there is a leak that must be repaired first. A shop will be better able to find it.
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You need to do more than just put the fittings on to convert to R134a.


The system must be flushed with a special solvent, then Its best to replace the dryer. Then it must be vacuumed down to 28 in. mercury for at least an hour (better fo 2 hrs), to remove moisture.

Then approx. 4 to 8 oz. of special oil is added that is compatible with both R12 and R134a.

Then the R134a is added, 1 1/2 lbs. And some dye, which we always ad so later, if it starts blowing warm, then we can find the leak easier.

Thats why you need to have a shop do it.