A/C Compressor Clutch Bearings 

KOYO DAC3052-3RR90 or Nachi DAC30520022
Koyo DAC3052-32RR9DS10Z, NSK 30BD5222FX


The bearing dimensions are: 52mm OD 30 mm ID, 22 mm depth
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A/C Compressor Clutch Bearing 30mm ID x 52mm OD x 22mm Thick CLIMAPARTS - RON101

Bearing Related Failures
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 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 clutch bearings are rare, and warranty allowances are usually associated with excessive noise symptoms only.

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.