In workshops, the exact check and adjustment of the V-belt tension is carried out using a special machine. This installation has special scales for new and used belts, as well as for certain types of engines and units. The V-belt has the correct tension when the pointer is against the corresponding adjustment value. If such a device is not available, the belt should be tensioned so that it bends when pressed with a finger in the middle between the pulleys by 3 mm.
Loosen the fastening nut on the axis of rotation of the air conditioning compressor without unscrewing it.
To tension the belt, turn the tensioning bolt -A-. Check the tension with your finger.
After that, tighten the fastening nut to a torque of 45 Nm.
When measuring the V-belt tension with the BMW tool -1-, the tension hook -2- of the tool must rest on the point of the tooth.