Remove the fan impeller, air conditioning compressor drive belt and generator. Loosen the bolt (1, Fig. 6.26) and remove the guide roller (2) of the alternator drive belt. Loosen the bolt (3) of the bracket, which must be removed and installed together with the belt tensioner. Remove the tension roller with the lever (4) by moving them in the direction of the arrow.
Loosen the bolts (1, Fig. 6.27) fasteners and remove the base of the alternator drive belt tensioner. Replace the sealing gasket (2).
The tensioner should be installed in the reverse order, and the following is required:
- the groove in the housing of the BMW X5 E53 drive belt tensioner must face the generator;
- center the drive belt tensioner, insert its mounting bolts, but do not tighten them;
- install the tension roller with the lever and tighten the new self-locking nut;
- tighten the bolts (1) securing the tension roller base.
Install the alternator, guide roller, alternator and air conditioning compressor drive belts. Check that the drive belts are correctly positioned on the pulleys and assemble the engine.