Checking the accessory drive belt
A - New belt; B - Wall wear - ribs are sharpened (on new belts they are trapezoidal); C - Cord exposure; D - Cracks on the back of the belt; E - Peeling of rubber from the base; F - Outer cord wear; G - Side cord break; H - Cracks across the ribs; J - Rib injury; K - Cracks of individual ribs; L - Contamination or stones stuck between the ribs; M - Tearing rubber on the ribs
1. The diagrams of the serpentine belt routing for auxiliary units are presented in Section Replacement of the auxiliary drive belt and elements of its tensioning mechanism.
2. With fingers (and using a flashlight if necessary) walk the entire length of the belt, feeling for cracks and delamination. Also check for abrasions and polished areas. The belt should be inspected from both sides, which means twisting it to check the condition of the reverse side. At the same time, check for rust, cracks and burrs on the pulleys. Shallow perpendicular cracks are allowed on the working surface of the belt. If these cracks do not extend beyond one rib and are not very deep, there is no need to replace the belt.
3. The drive belt tension is adjusted automatically. It is necessary to periodically check the condition of the belt, and if defects are found, replace the belt.
4. The belt tension is carried out by an automatic tensioner and does not require checking.
5. Turn off the engine, set the transmission to neutral. Raise and place the car on stands.
6. Mark the belt with chalk in a clearly visible place.
[Article text obtained from the website: MercedesMAN.ru]
7. Using a socket wrench, turn the engine by the crankshaft pulley bolt in the direction of normal rotation (clockwise) until the chalk marking appears again, carefully examine the condition of the belt tape along its entire length.
8. The belt tension can be checked by pressing firmly with your thumb and determining the degree of deflection. Measure the deflection with a ruler. If the distance between the pulley centers is between 180 and 280 mm, the deflection should be 6 mm. If the distance between the pulley centers is between 300 and 400 mm, the deflection should be 13 mm.
9. If one or more of the above damages are present, the belt must be replaced (see Chapter Engine).
10. Make sure the belt is seated correctly on the pulleys.
When installing the drive belt, place it correctly on the pulleys - it should be located strictly in the center of the pulley (even short-term operation of an incorrectly installed belt can lead to its damage).