auto air conditionings clutch related failures

Bearing Failure

Burnt Hub, Pulley, and/or ac clutch Coil

Inadequate voltage to the coil will result in overheating of the internal winding and cause the clutch hub to slip against the face of the pulley. A ac compressor in the stages of failing due to slugging or loss of lubrication, or operating under a high pressure condition will cause the ac clutchto slip. The slipping occurs continuously during ac compressor operation and can subject both the clutch and coil to extreme temperatures up to 1,200 degrees F. This will quickly destroy the ac clutch and its internal components. Visual evidence of this type of failure can be found in the illustrations on page 6. This type of failure is not warranted.

Noisy Bearing

If the complaint is noise related only, a defective clutch pulley bearing could be the source of the problem. Check for a rough or poorly operating bearing by holding the clutch armature hub stationary, and rotating just the pulley. If excessive noise or difficulty in ease of rotation is observed, the bearing may be suspect. However, as with the failed bearing situation described above, several factors can cause the bearing to become noisy or rough in operation. A rough bearing can also be one that is in the early stages of failing due to system problems involving extreme heat. This is usually the case if the compressor clutch has been operating sufficiently for some time and then becomes noisy. Most factory bearing defects become evident in the first hours of compressor operation. Warranty consideration for failed compressors and ac clutch described as noisy will be provided only if there are no obvious signs that the failure was caused by other factors.

Bearing failures are usually caused by system problems. Very seldom is a bearing itself the culprit of a failed or locked up compressor. For example, if the ac clutch slips severely due to a high pressure or low voltage condition, or due to compressor slugging, the excessive heat generated by the slipping will quickly melt and destroy the bearing seal. The bearing then loses its grease and locks up or falls apart, usually destroying the clutch in the process. This type of bearing failure is not covered under warranty, since the bearing was not the root cause of the problem. Warranty may be considered only if the bearing is intact, and there is no evidence of excessive heat, a compressor or a/c system problem, or signs of installation related problems. Manufacturing defects in cutch bearings are rare, and warranty allowances are usually associated with excessive noise symptoms only (see following condition).