BMW X5 E70 A/C compressor and magnetic clutch
Why does the A/C on an X5 E70 not cool even though refrigerant has been added?
The compressor's magnetic clutch may be broken, in which case the pulley does not lock onto the compressor shaft. If voltage reaches the compressor connector when the A/C is switched on but the compressor does not start, the clutch is probably faulty. The resistance of a broken coil is high on a multimeter.
How do you replace the magnetic clutch?
1. Remove the compressor. 2. Remove the torx screw and the cover. 3. Pull off the pulley and magnetic clutch with a puller; they are on tight. The clutch alone is usually enough. If the inner surface of the cover is worn, replace the whole set. The N52 compressors in the E70 have a magnetic clutch and an external control valve.
What should be considered when replacing the compressor?
No oil is added to the dryer, because the oil is in the compressor. The oil quantity is balanced between the old and the new compressor according to the workshop manual, at least 50 ml into the new one plus 10 ml extra. Leak tightness is tested with nitrogen pressure, because a vacuum test is not entirely reliable.