Compressor is possible but it could just be the clutch clearance that has increased for some reason, still dont know why it is RPM dependant. The clutch is the first thing to check and even replace. If expansion valve shuts, you will also loose cooling but dont have a clue why that should be RPM dependant.

Check the voltage on the battery also, unregulated output from the alternator does wierd things, and the alternator output is RPM dependant if unregulated. But again, a whole bunch of other things will stop, including the car if the alternator regulator has failed.

In short, running out of ideas.

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Saumil S. Patel