I've got the Kirk Evans bulkhead reduction kit and pulley setup that drives the compressor from the crank and the alternator from the compressor. I am on my third Sanden rotory compressor and this time I had new high and low pressure switches installed by an AC shop. With the compressor off, there are no issues. With the compressor on, at 2,500 the brand new compressor makes a metallic clanking noise. This is the same noise that occurred before the last 2 compressors failed. The noise builds up and if you let off on the revs, it slowly decreases. Is this noise from over-revving? Over pressurization? Defective compressor? Any ideas welcome. Thanks, Rob I've got the Kirk Evans bulkhead reduction kit and pulley setup that drives the compressor from the crank and the alternator from the compressor.A I am on my third Sanden rotory compressor and this time I had new high and low pressure switches installed by an AC shop. With the compressor off, there are no issues. With the compressor on, at 2,500 the brand new compressor makes a metallic clanking noise.A This is the same noise that occurred before the last 2 compressors failed. The noise builds up and if you let off on the revs, it slowly decreases. Is this noise from over-revving?A Over pressurization?A Defective compressor? Any ideas welcome. Thanks, Rob