Replacing the air conditioning compressor drive belt tensioner must be carried out in the following order.
Remove the fan shroud and front engine accessory guard. Press the drive belt tensioner on the hexagon (1) in the direction of the arrow and remove the A/C compressor drive belt (2).
Remove bolts (1, fig. 6.29) on the tensioner (3) drive belt from the back. Take out the tension roller with the lever (2) in the direction of the arrow and remove the tensioner (3) drive belt.
Tensioner installation should be carried out in reverse order, while it is necessary to check the cleanliness of the drive belt, put on the drive belt and check the correct position on the pulleys, the groove on the drive belt tensioner housing must be directed downwards (arrow, fig. 6.30).
Align the BMW X5 E53 drive belt tensioner, insert the bolts, but do not tighten, install the tensioner with lever and then tighten the bolts. Assemble the engine.