AC Compressor Test?

[PHillary]

Is there any home test(s) I can perform on my AC compressor to test if it works or not?

[BobFitz]

Originally Posted by PHillary

Is there any home test(s) I can perform on my AC compressor to test if it works or not?

If you have gauges yes, if not, not really

[John_AZ]

Griffiths has info:
Trouble Shooting the Porsche Air Conditioning System

Also in the WSM AC section.

J_AZ

[veleno]

Are you wanting to test if it works/turns on? If yes, you can put some freon in (if you're low/out) and if it cycles/kicks on then it works and you have a leak somewhere. If it doesn't then you have to trouble shoot whether it's the compressor, switch, fuse, etc...

However, I have read that you can wire it up directly to power but I'm not so sure about that method.

[kuehl]

If you don't have repair history records on the compressor and system, or if the compressor is questionable in any degree, the smart road to take would be to inspect the compressor.

After removing all refrigerant from the system, disassemble the compressor and inspect:

1) Front clutch hub... look for cracks in rubber bond, excessive wear of the clutch surface.

2) Pulley... bearing (rubber wiper seals are in good shape, no grinding when turned), and clutch surface.

3) Clutch coil.... you can test it with an ohm meter, should be 3 to 3.5 ohms nominal. No cracks in epoxy potting. As well, when the compressor is together you can test the clutch assembly by providing 12vdc, approx 2 to 5 amps min power, ground to compressor body and positive lead to the clutch coil wire, the front hub should "click" in quickly and the front hub should mate flattly with the pulley.

4) Opening up the compressor:
A) Shaft area wear front nose seal contacts is not corroded.
B) Aluminum wobble plate is smooth and no wear where piston half bearings contact.
C) Pistons OD's are clean, no scratches or grooves.
D) Cylinder bores, clean, no scratches or grooves.
E) Reed plate assemblies on front and back: no corrosion, no broken reeds, the vulcanized coating on the reed stop plates are intact.
F) Case grooves where o-rings sit are clean, no cracks.
H) Thrust bearings and races in good condition.
I) Residual compressor oil is clean; no gelling, no signs of debris (grey matter, ultra fine aluminum particles; use a 5x magnifier, stuff that should not be there).

If all looks well with the compressor get a seal kit, put it back together, replace your receiver drier and system o-rings, replenish the system with refrigerant oil, evacuate, charge and test.

944 AC

[John_AZ]

A few pictures:

Rebuild method for Nippondenso 10P15C A/C compressor

And when your done it will probably leak...

J_AZ

[kuehl]

Originally Posted by John_AZ

And when your done it will probably leak...

J_AZ

John,

Be nice!

[PHillary]

Probably right, think I am going to hook it up, see if it works and if not, its going to the trash man. Thanks all for the words of advice.

Paul

[John_AZ]

Originally Posted by veleno

Are you wanting to test if it works/turns on? If yes, you can put some freon in (if you're low/out) and if it cycles/kicks on then it works and you have a leak somewhere. If it doesn't then you have to trouble shoot whether it's the compressor, switch, fuse, etc...

However, I have read that you can wire it up directly to power but I'm not so sure about that method.

You can short the low Freon pressure switch, usually by the receiver dryer, if the clutch does not engage with a paper clip. DO not forget to remove when done.

If the clutch does not engage you can run a long wire from the battery POS to the compressor clutch lead that is usually along the frame about 12 inches in length. Separate the wire at the connection.

Engine off. Just tap the lead with the 12V POS lead wire. If you see the clutch engage = usually clutch OK. Compressor condition unknown.

Replace the wire at the connection.

J_AZ