For 1990-2009 cars

## Compressor Description Buick

The V-5 A/C compressor is belt driven from the engine crankshaft through the compressor clutch pulley. The compressor pulley rotates without driving the compressor shaft until an electromagnetic clutch coil is energized. When voltage is applied in order to energize the clutch coil, the clutch plate and hub assembly is drawn toward the pulley. Magnetic force locks the clutch plate and the pulley together as 1 unit in order to drive the compressor shaft.

When the compressor shaft is driven, the compressor pulls low-pressure, low-temperature vapor from the accumulator. The vapor is compressed into high-pressure, high-temperature vapor and pumped into the condenser. Refrigerant oil is carried with the refrigerant. The oil is used in order to lubricate the compressor. The compressor has a unique lubrication system. Compressor rotation acts as an oil separator, which removes some of the oil from the crankcase where the oil can lubricate the compressor mechanism.

When the engine is turned OFF while the A/C system is operating, the refrigerant in the system flows from the high-pressure side of the expansion (orifice) tube to the low pressure side until the pressure is equalized. This may be detected as a faint sound of liquid flowing (hissing) for 30-60 seconds. This is a normal condition.

For further information about the compressor operation, refer to V-5 Air Conditioning Compressor Service or Unit Repair.

## Compressor Description Oldsmobile

The A/C compressor is belt driven from the engine crankshaft through the compressor clutch pulley. The compressor pulley rotates without driving the compressor shaft until an electromagnetic clutch coil is energized. When voltage is applied in order to energize the clutch coil, the clutch plate and hub assembly is drawn toward the pulley. Magnetic forces lock the clutch plate and pulley together as one unit in order to drive the compressor shaft.

When the compressor shaft is driven, the following events occur:

1. The compressor pulls low-pressure, low temperature vapor from the accumulator.
2. The compressor compresses the vapor into high-pressure, high temperature vapor.
3. The compressor pumps the vapor into the condenser.

The refrigerant oil is carried with the refrigerant. The refrigerant is used to lubricate the compressor.

The compressor is equipped with the following components:

• | A pressure relief valve (4)

• | An A/C high-pressure cut-out switch (5)

These components are placed in the system as safety devices

Refer to Air Conditioning Compressor Replacement for further information about compressor operation.