Removal and installation the alternator V-belt / tensioning the V-belt (BMW 5 Series E34)

Engines M20, M21, M30, M40 (2-valve engines except 525td/tds)

For instructions regarding the M50 engine, see the end of the section.

Removal

Remove the fan.



Loosen bolt 1, loosen nuts of bolts 2 and 3. Turn bolt 3 in the direction of the arrow, thereby loosening the tension of the V-belt.

Loosen the V-belt of the power steering pump in the same way. Then remove the V-belt of the alternator.

Installation

Before installation, check the V-belt. If the edges are frayed, cracks or tears are present, be sure to replace the V-belt.

Apply and tighten the V-belt.

V-belt tension

• Tighten tension roller 2 with a torque wrench to a tightening torque of 7 Nm.
• Tighten the nut of bolt 3.

In workshops, precise checking and adjustment of the V-belt tension is performed using a special installation.



The tension hook 2 of the device must be applied in the middle of the teeth. The pointer of the indicator must be in the green or yellow sector of the scale for the corresponding engine. In addition, the specified value on the scale is different for a new and used belt. If the pointer is not in the specified sector of the scale, adjust the tension of the V-belt.



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 5 mm. After this, the tension of the V-belt should be adjusted at the earliest opportunity using the BMW device.

Tighten bolt 1 and nut 2.

Install and tension the power steering pump V-belt.

Install the fan.

Engine M50 (520i, 525i produced since May 1990.)

The 4-valve engine is equipped with a wider V-ribbed belt, which drives the generator, water pump and power steering pump. With the appropriate equipment, the air conditioner compressor is driven by a second V-ribbed belt.

Removal

If equipped, remove the A/C compressor V-belt as described below.



Place the head of the wrench on the tension roller bolt. When slowly turned clockwise, the hydraulic tensioner element 1 is compressed. Remove the V-ribbed belt.

Installation

Apply a new V-ribbed belt according to the diagram shown, while moving the tension roller completely to the right, just as when removing. Pay attention to the correct position of the grooves on the belt pulleys.



Unload the tension roller. The tension is created by a hydraulic tension element and is not adjustable.

Engine M51 (525td/tds)

The 2.5L diesel engine uses a wider ribbed V-belt that drives the alternator, water pump and power steering pump.



Place a powerful screwdriver or similar lever against the tensioner, see figure. Compress the belt tensioner and remove the V-ribbed belt.



Apply a new V-ribbed belt according to the diagram shown, while moving the tension roller completely to the right, just as when removing. Pay attention to the correct position of the grooves on the belt pulleys.

Unload the tension roller. The tension is created by a hydraulic tension element and is not adjustable.

If removed, install the engine compartment sump.



Lower the car.

[Examine the original source using the link on the website: BMWMAN]