Two belts are used to drive engine accessories, The larger belt is used for the A/C compressor while the thin belt is for the alternator, coolant pump and steering pump. In particular, when intending to reassemble the old belts, the direction of the rotation should be indicated. Here, one can make a use of BMW special tools: 11 5 050 and 11 5 040 with which the cooling fan and clutch should be loosened and removed from the coolant pump and writers noted that the 32 mm cooling fan nut has left-hand thread. Sometimes it may be required to take off the fan cowl on the radiator, if it gets in the way of the work. As for the puller, the instructions are as follows: Rotate the A/C belt tensioner in the indicated direction using a hex head or Torx socket; then, the belt can be slipped off the pulleys; examine it for cracks and the deposits of the coolant and oil if present and use a new one if any of those conditions is met. For reinstallation, turn the A/C belt tensioner anti-clockwise, put the belt over the pulleys, and then remove the tension from the tensioner. To release the belt, do as follows; the A/C compressor belt has to be detached first, then with regard to the drive belt tensioner cap, turned in the indicated direction, the belt isn't hard to remove, and before reinstalling, it needs to be checked for signs of wear and tear or any residual substance which might have accumulated on the belt and replacing it if necessary. During the reinstallation perform a check to make sure that the belt is placed correctly on the pulleys and if the old belt is being reused then ensure you refer to the marks that defined the direction of rotation.