Drive Belt: Testing and Inspection

WM 137801 Checking drive belt on DFI engines

Preliminary work

1. Remove intake pipe (Y-shaped pipe) upstream of throttle valve. => 243519 Removing and installing air box for throttle housing on DFI engines (intake pipes upstream of throttle valve) - section on "Removing"

Information

Damage symptoms and general information

CAUTION

Risk of damage to drive belt.

- If the drive belt is removed when it is hot, it may become deformed and damaged.

-> Never remove drive belt when it is hot.

CAUTION

Drive belt breaks and becomes jammed

- Risk of damage to components (trim panels, electric cables, etc.)
- Sealing ring on crankshaft vibration balancer can start to leak
- Vibration balancer can overheat and lose its strength

-> Following belt breakage, check adjacent components and the interior of the engine compartment for damage, and repair or replace damaged parts if necessary.
-> Find out why the belt broke. Check deflection rollers or crankshaft vibration balancer for prior damage.
-> If the drive belt is jammed, replace vibration balancer.

WARNING

Danger of injury.

- The vehicle fans can continue running or start up automatically.

-> The power supply to the fans must be disconnected (remove fuse) or the battery disconnected before starting work on the radiator or radiator fans.

Information

- The following table indicates damage which necessitates replacement.





Damage symptoms for drive belts






Checking drive belt

Information

- If spark plugs must be changed in the course of maintenance operations, the drive belt should be checked when the spark plugs are removed. The engine can then be cranked easier.

1. Using chalk, mark the drive belt in the area around the tensioning roller. => Marking on drive belt





Marking on drive belt

2. Turn engine at the vibration damper in the rolling direction using a socket wrench until the chalk mark is at the same place again. While turning at the crankshaft, check the drive belt at the deflection rollers for signs of damage.
3. When turning the engine, check deflection rollers for smooth operation, intact running track and play. Replace noisy and damaged rollers.

Subsequent work

1. Install intake pipe. => 243519 Removing and installing air box for throttle housing on DFI engines (intake pipes upstream of throttle valve) - section on "Installing"