Drive Belt: Service and Repair

WM 137819 Removing and installing drive belt on 4.8 l DFI engine

Preliminary work

1. Remove intake manifold (air box) from throttle housing as far as the mass air flow meters. => 243519 Removing and installing air box for throttle housing on DFI engines (intake pipes upstream of throttle valve) - section on "Removing"

Information

NOTICE

Drive belt removed incorrectly

- Risk of damage to drive belt

-> Only remove the drive belt when it is cold.

-> Replace damaged drive belt.

NOTICE

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

Rotating components
- Danger of limbs being trapped or severed

->Disconnect power supply to the drive motor of components or to the battery.





Drive belt, Turbo M48/51









Drive belt on naturally aspirated engine, M48/01









Belt drive






Removing drive belt

1. Mark the rolling direction of the drive belt with chalk.
2. Open coolant hose connecting clip. -10- Lift coolant hose aside.

Information

- Using an open-ended wrench can damage the belt tensioner.

- Using a tool with a width across flats of 32 mm can damage the belt tensioner.

3. Relieve and remove the drive belt. To do this, turn the belt tensioner clockwise at the hexagon -9- using a ring wrench (width across flats 30) or change-over ratchet with socket and remove the drive belt from the tensioning roller -6-. Then relieve the belt tensioner slowly.





Drive belt on naturally aspirated engine, M48/01





4. Remove the drive belt from all pulleys. -1 to 8-

Installing drive belt

Information

- Using an open-ended wrench can damage the belt tensioner.

- Using a tool with a width across flats of 32 mm can damage the belt tensioner.

1. Fit used drive belt in the rolling direction according to removal marking. Fit drive belt straight on all pulleys without tilting it (leave loop in front of tensioning roller -6- ) -1 bis 8-. Finally, turn the belt tensioner clockwise at the hexagon -9- using a ring wrench (width across flats 30) or change-over ratchet with socket and place the drive belt around the tensioning roller -6-. Then relieve the belt tensioner slowly.





Drive belt on naturally aspirated engine, M48/01





2. Check that the drive belt is positioned correctly on the pulleys. => Belt drive





Belt drive





3. Turn engine clockwise at the vibration balancer and check that the drive belt is fitted correctly. This work is much easier during a service because the spark plugs are removed.
4. Move coolant hose into the correct position and close coolant hose connecting clip. -10-

Subsequent work

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