Toothed Belt
Toothed Belt
Special tools, testers and auxiliary items required
• Diesel Injection Pump Locking Pin (3359)
• Crankshaft Stop (T10050)
• Counterhold Tool (T10172)
• Special Wrench, Long Reach (T10264)
• Locking Tool (T10265)
• Torque Wrench (V.A.G 1331 (5-50 Nm))
• Torque Wrench (V.A.G 1332 (40-200 Nm))
• Toothed belt overview. Refer to => [ Toothed Belt Overview ] Toothed Belt Overview.
Requirements
• Ignition is turned off.
• Engine must be cold.
• Adjustments to the toothed belt may generally only be performed when the engine is cold, because the indicator position of the tensioning element changes depending on engine temperature.
• The engine mount bracket must be removed to remove/install the belt tensioner. Refer to => [ Engine Mount and Bracket ] Engine Mount and Bracket.
Removing
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
- Remove the fuel filter. Refer to => [ Fuel Filter ] Fuel Filter.
- Remove the auxiliary fuel pump. Refer to => [ Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump) ] Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump).
- Disconnect the connector - 1 - from the engine coolant temperature sensor on radiator outlet, open the clips - arrows - and remove the upper toothed belt guard.
- Remove the right front wheel housing liner.
- Remove the ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Remove the vibration damper.
- Remove the lower and center toothed belt guard bolts - arrows -.
- Remove the coolant pipe nut - 1 -.
- Rotate the engine to Top Dead Center (TDC) and secure the crankshaft toothed belt gear using the crankshaft stop (T10050). Push the crankshaft stop from the front side of the toothed belt gear into the teeth. The toothed gear must be in the "12 o'clock" position.
• The marks on the crankshaft toothed belt gear - 2 - and the crankshaft stop (T10050) - 1 - must align. The pin on the crankshaft stop (T10050) must engage in the hole on the sealing flange.
- Mark the rotational direction of the toothed belt.
- Loosen the bolts - 1 - for the camshaft gear.
- Loosen the coolant pipe bolt - 1 - and then the bolts for the high pressure fuel pump toothed belt gear - 2 -.
- Loosen the nut - 1 - on the tensioner and turn the tensioner eccentric pulley counterclockwise in the - direction of the arrow - using the special wrench, long reach (T10264) until it is possible to lock the tensioner using the locking tool (T10265).
- Now, turn the tensioner eccentric pulley clockwise in the - direction of the arrow - all the way and tighten the nut - 1 - by hand.
- First, remove the toothed belt from the idler roller and then from the remaining gears.
Installing and Tensioning
Requirements
• Ignition is turned off.
• Engine must be cold.
• The locking tool (T10265) must be inserted in the tensioner and the roller must be secured on the right stop.
• Secure the crankshaft using the crankshaft stop (T10050).
• Adjustments to the toothed belt may generally only be performed when the engine is cold, because the indicator position of the tensioning element changes depending on engine temperature.
• The engine mount bracket must be removed to remove/install the tensioner. Refer to => [ Engine Mount and Bracket ] Engine Mount and Bracket.
Procedure
- Rotate the camshaft hub using the counterhold tool (T10172) and the adapter (T10172/4) until it can be secured in place. Use at least one bolt - 1 - tightened by hand to do that.
- Secure the camshaft hub using the diesel injection pump locking pin (3359). To do this, push the pin through the empty outer slot and into the cylinder head bore.
- Loosen the bolts - 1 - that were tightened by hand.
- If necessary, rotate the high pressure fuel pump hub with a screwdriver at the bolt heads - 1 - until it can be secured.
- Secure the high pressure fuel pump hub using the diesel injection pump locking pin (3359). To do that, slide the pin into the hole outside the toothed belt sprocket.
- Rotate the camshaft gear and high pressure fuel pump gear clockwise in their slots as far as the stop.
- Install the toothed belt on the crankshaft gear, the tensioner, the camshaft gear, coolant pump toothed belt gear and the fuel high pressure toothed belt gear.
- Lay the toothed belt on the tensioner last.
- Loosen the tensioner nut and remove the locking pin (T10265).
• Make sure the tensioner is properly positioned in the rear toothed belt guard - arrow -.
- Carefully rotate the tensioner eccentric pulley clockwise using the special wrench, long reach (T10264) until the indicator is centered in the base plate gap - 2 -.
• Make sure the nut - 1 - does not rotate with it.
- Hold the tensioner in this position and tighten the nut on it.
• Tightening specification, see - item 6 - in the => [ Toothed Belt Overview ] Toothed Belt Overview.
- Position the counterhold tool (T10172) as illustrated. Push the (T10172) in the - direction of the arrow - and hold the camshaft gear tensioned.
- In this position, tighten the bolts - 1 - for the camshaft gear and high pressure fuel pump toothed belt gear.
• Tightening specification: 20 Nm.
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft at least two rotations in engine rotation direction and position it just before cylinder 1 TDC.
- Position the crankshaft stop (T10050) on the crankshaft toothed belt gear again.
- Now, turn the crankshaft in engine rotation direction until the crankshaft stop tab - arrow - engages the sealing flange.
• In the following check, only the camshaft and crankshaft are secured. It is difficult to find the securing point on the high pressure fuel pump hub. A small deviation - arrow - does not affect engine operation.
- Check if:
• the camshaft hub can be secured using the diesel injection pump locking pin (3359) and
• the tensioner indicator is centered with or a maximum of 5 mm to the right of the base plate gap.
If the camshaft hub cannot be secured:
- Pull the crankshaft stop (T10050) toward the back until the tab opens the hole.
- Rotate the crankshaft opposite engine rotation direction until it is slightly past TDC.
- Now, rotate the crankshaft slowly in engine rotation direction until the camshaft hub can be secured.
- After securing, loosen the bolts on the camshaft toothed belt gear.
If the crankshaft stop (T10050) tab is to the left of the hole
- Rotate the crankshaft in engine rotation direction until the crankshaft stop tab engages the sealing flange.
- Tighten the bolts on the camshaft toothed belt gear.
• Tightening specification: 20 Nm.
If the crankshaft stop (T10050) tab is to the right of the hole
- Rotate the crankshaft slightly opposite engine rotation direction.
- Now, rotate the crankshaft in engine rotation direction until the crankshaft stop tab engages the sealing flange.
- Tighten the bolts on the camshaft toothed belt gear.
• Tightening specification: 20 Nm.
Continued
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft at least two rotations in engine rotation direction and position it just before cylinder 1 TDC.
- Check again.
If the camshaft hub can now be secured:
- Tighten the bolts as follows:
• Tighten the camshaft toothed belt gear bolt an additional 45° (1/8) turn. Counterhold it using the counterhold tool (T10172) and the adapter (T10172/4).
• Tighten the high pressure fuel pump toothed belt gear bolt an additional 45° (1/8) turn. Counterhold it using the counterhold tool (T10172) and the adapter (T10172/8).
- Install the lower and center toothed belt guard bolts - arrows -.
• Tightening specifications, see - item 27 - in the => [ Toothed Belt Overview ] Toothed Belt Overview.
- Install the vibration damper.
• Tightening specification, see - item 28 - in the => [ Toothed Belt Overview ] Toothed Belt Overview.
- Install the ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Install the upper toothed belt guard.
- Make sure the upper toothed belt guard is clipped to the cylinder head cover correctly.
• The camshaft gear is not shown in the illustration.
- Press the upper toothed belt guard in the area with the clips - arrows - against the cylinder head cover until the clips engage with each other. Use a screwdriver to press the guard if necessary.
- Check the clearance between the hub and the upper toothed belt guard.
- Install the right front wheel housing liner.
- Install the noise insulation.
The rest of the installation is basically a reverse of the removal procedure. When doing this note the following:
• Route the fuel hoses free of kinks.
• Ensure the fuel hoses are seated securely.
• Do not interchange the supply and return lines (the return line is blue or has a blue mark, the supply line is white or has a white mark).
• Clip the fuel hoses into the retainers.
- Install the auxiliary fuel pump. Refer to => [ Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump) ] Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump).
- Install the fuel filter. Refer to => [ Fuel Filter ] Fuel Filter.
- Install the engine cover. Refer to => [ Engine Cover ] Engine Cover.