Aftermarket replacement manufactured by Sanden-Behr, this compressor replaces the Nippondenso 7SB16C, which was replaced with the 7SBU16C.  Original Denso units have a high failure rate.  The cause of the original failures are discharge reed valves breaking in the bottom-most piston cylinder.  The main symptom of this failure is the compressor not pumping, because of internal pressure bleeding between the suction and discharge sides of the compressor.  This breakage can also cause the pump to 'lock up' if metal gets wedged in the cylinder walls, and can cause condenser restrictions.

 

Denso 7SB16C and 7SBU16C compressors have a control valve.  A control valve measures refrigerant and adjusts the angle of the swash plate, to which the pistons are connected, and controls the stroke of the pistons.  If high pressure is measured, the control valve adjusts to shorten the stroke of the pistons, so less pressure is produced.  If, upon installation of a new compressor, there seems to be no 'pumping' from the compressor, it may be necessary to remove the control valve and blow off excess oil.  The control valve may be sensing no pressure and presuming the system is emtpy of refrigerant.

 

This Sanden-Behr replacement is built with an improved design and more durable reed material for longer A/C Compressor life on your BMW vehicle.

 

Cross reference: