That's the speed senosor.

Nippondenso AC compressors were used in lots of Japanese cars, so finding one in the junkyard won't be too difficult.

Bad thing is that the only way the speed sensor can get "worn" so it makes noise is for the main shaft of the compressor to move back in the bearings. The speed sensor is a Hall Effect pickup, shouldn't actually touch anything.

Check for grey or black residue in the AC components. If you find any, you will need to very carefully flush EVERYTHING and install a new or properly rebuilt AC compressor WITH an inline filter on the suction side.

I've been advised to avoid any Nippondenso AC compressors rebuilt by Four Seasons, they almost always fail and the warrenty won't be honored due to "contamination". I've heard this is because there is junk in them when delivered, but I don't know this for a fact, having never taken one apart. You really want to get one rebuilt in Japan. Those are very good.

A good used one from the junkyard will work, too.

You have either a 10P15C or 10PA15C compressor, I believe. Both have four sections. ON the 10P15C, the center two sections are equal length, on the 10PA15C the two center sections are unequal length.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!