The timing belt tensioner is a load-bearing pulley located on an adjustable axle. Its main function is belt tension; additional functions are to damp drive vibrations and increase the angle of the camshaft pulley wrap.

1. A8 (4D2, 4D8)
2. A8 Saloon (4D2, 4D8)
3. A8 / S8 (4D2, 4D8)
4. A6 (4B2, C5)
5. A6 Saloon (4B2, C5)
6. A6 / S6 (4B2, C5)
7. A4 (8D2, B5)
8. A4 Saloon (8D2, B5)
9. A4 / S4 (8D2, B5)
10. A4 Avant (8D5, B5)
11. A6 Avant (4B5, C5)
12. A6 / S6 Avant (4B5, C5)
13. PASSAT Variant (3B5)
14. PASSAT Wagon (3B5)
15. PASSAT Estate (3B5)
16. PASSAT (3B2)
17. PASSAT Saloon (3B2)
18. ALLROAD (4BH, C5)
19. ALLROAD Avant (4BH, C5)
20. A4 (8E2, B6)
21. See more in applications

The operation of the timing belt tensioner

The VAICO brand Tensioner, timing belt is a bearing with a pulley on the outer cage. Depending on the design, the tensioning mechanism can be made in the form of an eccentric pressed into the inner bearing race, or placed on a separate bracket. The bearing cage is packed with grease and covered with a lip. You can order an automatic tensioner, it is a little more complicated, but the roller itself has no fundamental differences.

Timing belt tension is designed for a specific force and must be consistent. Selecting a timing belt tensioner pulley that is too loose can cause the belt to slip through the timing belt teeth. This is unacceptable, since it will lead to a shift in the phases of the valve operation relative to the movement of the pistons.