Table of contents: Visual inspection of condition ↓ Checking the tension of the fuel… ↓ Timing Belt Tension ↓
The 2.5 l diesel engine has 2 toothed belts, respectively for driving the camshafts and the high-pressure fuel pump.
Visual inspection of condition
1. Remove the top engine cover, refer to Section Removal and installation the upper engine cover/lower engine compartment protection/subframe.
2. Remove the upper timing belt cover, refer to Section Removal and installation the timing belt.
3. Check the timing belt for the following damage:
- Cracks, transverse tears.
- Stratifications (toothed belt housing, tension branch).
- Chips on the toothed belt housing.
- Fraying of the tension branch.
- Surface cliffs (plastic shell)
- Traces of oil and grease.
A belt that is damaged must be replaced immediately (work of the service station).
Checking the tension of the fuel injection pump drive belt
Warning: The timing belt does not need to be tensioned during maintenance because the belt is tensioned automatically by the roller.
1. Check whether the marks (1) and (2) on the tension roller match. If the marks do not match, tighten the timing belt.
Timing Belt Tension
1. Loosen the tension roller mounting nut using a socket wrench or head, such as AUDI-3078 (1). In this case, the tension roller must be held from turning with a socket wrench.
2. Turn the tension roller counterclockwise with the socket wrench (2) (in the direction of the arrow in the illustration) so that the pointer (3) on the tension roller is opposite the mark (4). In this position, tighten the tension roller mounting nut with a spanner or socket to a torque of 36 Nm.
3. Reinstall the upper timing belt cover, refer to Section Removal and installation the timing belt.
4. Install the engine top cover, refer to Section Removal and installation the upper engine cover/lower engine compartment protection/subframe.