A/C Compressor Clutches & Parts

The A/C compressor clutch is a significant component of the A/C System. The A/C compressor itself is activated by an electronic clutch. As the A/C is switched on a drum inside the belt pulley is magnetized, this attracts and locks the belt drive in place so that it only adds resistance when engaged. Without a properly functioning clutch the compressor will not engage correctly and you will be left sweating.

Like all moving parts, the compressor clutch can have problems, anything from just sticking or slipping, to tearing itself apart due to centrifugal force. They can slip because they wear out, they can even chew up the belt if warped. Slipping can cause the performance of the A/C system to suffer, providing less than ice cold cooling or none at all. Sticking can negatively impact your fuel economy and drastically increase the cost of your commute!

When diagnosing a failed A/C compressor/clutch assembly, keep in mind that there are several possible causes for the failure, and that the least expensive repair may not thoroughly or permanently fix the A/C system. What may appear as a simple clutch failure is sometimes the result of other system problems such as: oil starvation (due to loss of refrigerant or restricted flow), low voltage to the clutch coil, or high pressure (due to clogged condenser or non-operating condenser fan, improper refrigerant or overcharge). If high-side pressure climbs to an excessive amount, the compressor will overheat, and the lubricant will melt out of the clutch bearing and cause prompt failure. These conditions will damage internal compressor components, and just replacing the clutch assembly will lead to another failure.

The only way to properly repair this type of failure is to diagnose the entire system. When replacing the compressor clutch, replace related items like: accumulator/filter drier, orifice tube/expansion valve, and thoroughly flush the system to prevent voiding the warranty. Also beware that clutch failure for any reason can damage the compressor shaft seal, nose, and bearing, and this damage may be difficult to see. The heat generated by clutch failure can distort the nose on any compressor, which will cause the replacement clutch assembly to fail as well. In these cases, the entire compressor/clutch assembly should be replaced, along with complete system repair.