Drive Belt: Service and Repair
WM 137819 Removing and installing drive belt
Preliminary work
1. Remove connecting tube (Y-shaped pipe) from air cleaner to engine. -> 243519 Removing and installing air box for throttle housing (Y-shaped pipe) - section on "Removing" 243519 Removing and installing cowl for throttle housing (Y-pipe)
Removing drive belt
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.
Information
- The pictures shown in this document may differ from the original.
- However, this does not affect the validity and relevance of the pictures.
Information
The connection between the full-throttle ventilation pipe and intake pipe on the turbocharger is a one-way coupling and will be damaged irreparably once opened -4-. Leave this connection closed and pull the drive belt through in an upward direction.
Oil separator for positive crankcase ventilation - turbo engine
Installation position of drive belt
1. Mark the running direction -arrow- of the drive belt with chalk.
Marking on drive belt (shown as an example)
2. Unclip the front coolant hose -1- from the holder on the timing-case cover -2-.
Hose
3. Turbo only:
Release the check valve -2- and then pull the check valve -1- out of the intake distributor.
Check valve for positive crankcase ventilation
4. Turbo only:
Release clamps -1, 2- on the check valve.
Removing clamps
5. Turbo only:
Pull off hoses at the check valve. -arrows-.
6. Turbo only:
Disconnect and pull off wastegate line at the clamp -1-.
Wastegate line
7. Relieve and remove 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.
To do this, use a ring wrench (width across flats 30) or a socket to turn the belt tensioner clockwise and remove the drive belt from the tensioning roller. Then relieve the belt tensioner slowly.
Belt tensioner hexagon
Loosening the belt
8. Remove the drive belt from the pulleys and rollers and pull it up over the full-throttle ventilation pipe to the check valve and out of the vehicle.
Installing drive belt
Information
- The pictures shown in this document may differ from the original.
- However, this does not affect the validity and relevance of the pictures.
Information
- The figure => Components shows the complete belt threading course. The pulleys are numbered according to fitting sequence.
Components
Belt drive
1. Bend the drive belt to form a loop and guide it through between the coolant pump pulley -1- and crankshaft pulley -5- towards to the tensioning roller -8-.
Fitting drive belt - Step 1
2. Place the top part of the belt loop over the coolant pump pulley -1-.
Fitting drive belt - Step 2
3. Place the lower part of the belt loop around the crankshaft pulley at the bottom -5-.
Fitting drive belt - Step 3
4. Guide the belt section from the coolant pump pulley -1- around the deflection roller -2- on cylinder bank 5 - 8.
Fitting drive belt - Step 4
5. Then guide the section of the belt around the air-conditioning compressor pulley -3- at the bottom.
Fitting drive belt - Step 5
6. Lay a loop around the power-steering pump -4-.
Fitting drive belt - Step 6
7. Lay the loose end of the drive belt from the coolant pump downwards and around the generator pulley -6- and deflector roller -7- of cylinder bank 1 - 4.
Fitting drive belt - Step 7
8. Gather the belt section between the deflection roller -7- of cylinder bank 1 - 4 and the crankshaft pulley -8- to form a loop and guide it upwards to the tensioning roller -8-.
Fitting drive belt - Step 8
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.
9. Use a ring wrench or socket (width across flats 30) to turn the belt tensioner in a clockwise direction at the hexagon.
Belt tensioner hexagon
Loosening the belt
10. Lay the drive belt on the tensioning roller. Slowly relieve the tensioning roller.
11. Check that the drive belt is routed correctly. => Components
12. Check that the drive belt is seated correctly on the pulleys.
13. Clip the coolant hose -1- into the holder -2-.
Hose
14. Turbo only:
Connect the wastegate line at the clamp -1-.
Wastegate line
15. Turbo only:
Attach the check valve -1- to the air box and fit a new clamp -2-.
Check valve for positive crankcase ventilation
16. Turbo only:
Attach hoses to the check valve and fit with new clamps.
Subsequent work
1. Fit connecting tube (Y-shaped pipe) from air cleaner to engine. -> 243519 Removing and installing air box for throttle housing (Y-shaped pipe) - section on "Installing" 243519 Removing and installing cowl for throttle housing (Y-pipe)