Most vehicles today come with a compressor-based air cooling system that requires two row angular ball bearings to operate. These bearings are one of the weakest components in the air conditioning structure as they are used each time your engine is running, regardless of AC activity. As a result, the bearings gradually wear out and start producing noises or, quite simply, break. If that is the case, a vehicle inspection might be required and once the fault in the bearing is determined, it will need to be replaced. There are around five common sizes fitted in automobile compressors, but the overall number of bearing-types reaches over 40 variants.