The photo shows the tensioner of the poly V-belt for the generator, servo pump and viscous fan:
- 1 - protrusion for installing an open-end wrench;
- 2 and 3 - holes for fixing the tensioning device in the unloaded state.
When the holes are aligned, the corresponding pin is inserted into them.
Fixing the tensioner of the poly V-belt for the generator, servo pump and viscous fan: the spring-loaded pivot lever (2) is swung to the right with an open-end wrench (in the direction of the arrow) until the pin (1) can be inserted into both matching holes.
To tension the V-ribbed belt of the air conditioning compressor, loosen the fastening bolts (1 and 3) on the tension roller console (4). Then install the torque wrench (2) on the hexagon of the tension roller console and tighten it by 25 Nm in the direction of the arrow. Tighten the fastening bolts.
Audi no longer includes this maintenance item, but we still think it's a good idea to have a preventative check done anyway:
- To check the belt, turn the engine over completely several times.
- This is the only way you can really inspect all the surfaces of the belts. Often the belts have only one single crack, which when inspected may be located exactly on the belt pulley.
- Replace torn or frayed belts immediately.
Checking the tension of V-belts and V-ribbed belts
The topic of V-belt tensioning in Audi is largely outdated, because:
1. The automatic tensioner of the large poly V-belt in four- and six-cylinder engines ensures that it is always correctly tensioned, so the most that can be done is to check the functionality of the belt tensioner.
2. When you press hard with your finger on the tensioned belt, it should bend, resisting, and the tension roller should turn to the side. When the belt is released, the roller swings back and tightens the belt. If the belt hangs freely between the belt pulleys, then the tension roller is faulty (or forgot to remove the locking pin from the tensioner).
3. The V-belt of the water pump in the four-cylinder engine is set to a fixed setting that cannot be varied. If the belt is loose and therefore the belt slips too much on the belt pulley, the V-belt must be replaced.
4. Ideal tension: When pressing hard with your thumb, the belt between both belt pulleys should deflect by approximately 5 mm.
5. The short poly V-belt, which drives the air conditioning compressor on a four-cylinder engine, is adjusted during initial installation and maintains this tension throughout its entire service life.