1998 Pontiac Grand Prix Air Compressor needs replaced

Tiny
PGHMOM
  • MEMBER
  • 1998 PONTIAC GRAND PRIX
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 10,500 MILES
Just bought a used 98 Grand Prix for my son. It seemed to be in good shape, but we have had two problems in the last month. First, replaced igition switch. Mechanic took 7 hours to figure it out and charged us a whopping $543! I was furious. Now the air compressor went out. He is telling us this is a 600-700 repair with a rebuilt compressor. What is the fair market charge for this repair? I'm ready to have it towed out of his garage, but it is hard to find an honest mechanic anymore.
Thanks
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Saturday, October 18th, 2008 AT 3:27 PM

4 Replies

Tiny
RASMATAZ
  • MEMBER
You sure its the compressor or its just low or no freon and the compressor is not kicking On. The price to repair is about right but it really depends what's really wrong-
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Saturday, October 18th, 2008 AT 3:37 PM
Tiny
PGHMOM
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My mechanic took the belt off and said the motor runs without it. How do you know if it just needs freon? I'm just a single mom doing it all. And I really know nothing about cars. Tired of being taken advantage of at the auto shop. Thanks
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Saturday, October 18th, 2008 AT 4:43 PM
Tiny
RASMATAZ
  • MEMBER
I'm not an expert in AC-if there's no freon the compressor will not kick on. The only way to tell is to hook a manifold gauges and read the Low/High pressures.

How to tell if your A/C system needs refrigerant: look at the LOW pressure gauge reading when the engine is OFF. On an 80 degree day, the LOW gauge should read about 56 psi or higher if the A/C system contains an adequate charge of refrigerant. On a 90 degree day, the LOW side reading should be about 70 psi or higher. If the LOW gauge reading is less than this, the A/C system probably needs some additional refrigerant.A/C COOLING PROBLEM?

The most likely cause of an automotive air conditioner cooling problem is no refrigerant in the system. If the refrigerant has escaped past a leaky compressor or O-ring seal, leaked out of a pinhole in the evaporator or condenser, or seeped out through a leaky hose, the leak needs to be identified and repaired before the system is recharged.

On many systems, the compressor will not turn on if the refrigerant is low because the "low pressure safety switch" prevents the compressor clutch from engaging if system pressure is low. This protects the compressor from possible damage caused by a lack of lubrication.

One of the first things you should check, therefore, is compressor engagement. If the compressors magnetic clutch is not engaging when the A/C is turned on, the problem may be a blown fuse or a wiring problem. If the fuse is blown, replacing it may restore cooling temporarily. But the underlying reason for the fuse blowing in the first place needs to be identified and corrected to prevent the same thing from happening again.

If the magnetic clutch is receiving voltage but is not engaging the compressor, the clutch is defective and needs to be replaced. If there is any evidence of leakage around the compressor shaft seal, the seal should also be replaced.

If the clutch works but fails to turn the compressor (the belt may squeal in protest!), The compressor has seized and needs to be replaced.

Compressor failures are usually the result of loss of lubrication, which in turn may be due to low refrigerant in the system, a blockage (such as a plugged orifice tube which prevents refrigerant and oil from circulating to the compressor), loss of lubricant due to leaks or improper service procedures (not adding oil to the system to compensate for oil lost through leakage or component replacement), or use of the wrong type of lubricant
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Saturday, October 18th, 2008 AT 4:53 PM
Tiny
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  • MEMBER
I really appreciate the discussion, it gives me a place to start with another mechanic. Thanks.
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Saturday, October 18th, 2008 AT 5:40 PM

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