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) (for tensioning roller A)
• Locking Tool (T10265)
• Special Wrench, Long Reach SW 8 (T10409) (for tensioning roller B)
• Torque Wrench (5-50 Nm) (V.A.G 1331)
• Torque Wrench (40-200 Nm) (V.A.G 1332)
Different Tensioning Roller Versions
• There are 2 versions of tensioning rollers installed. It is possible to exchange them for one another. When adjusting, first check which tensioning roller is installed.
Pay attention to the different directions of rotation for the tension roller
Characteristics of tensioning roller A:
• Locking tool (T10265) required for assembly.
• Make sure the tensioning roller fits correctly inside the toothed belt guard, refer to => [ Tensioning Roller Position Inside the Cylinder Head ].
• Tension the toothed belt by turning the tensioning roller eccentric pulley clockwise
Characteristics of tensioning roller B:
• No locking tool needed.
• The tension roller does not fit in the toothed belt guard.
• Tension the toothed belt by turning the tensioning roller eccentric pulley counterclockwise.
=> [ Tensioning Roller A ]
=> [ Tensioning Roller B ]
Tensioning Roller A
Removing
• The toothed belt may be adjusted only when the engine is cold because the position of the pointer on the tensioning roller will change due to the temperature of the engine.
A used toothed belt could be destroyed if the running direction is reversed.
• Before removing the toothed belt, mark the running direction with chalk or a felt tip pen for reinstallation later.
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
- Remove the noise insulation.
- Remove the coolant expansion tank bolts - 3 -.
- Disconnect and remove the connector from the coolant expansion tank - 2 -.
- Set the coolant expansion tank - 2 - aside.
Very hot fuel can burn your skin.
• The temperature of the fuel lines and may reach 100 °C (212 °F) after stopping the engine. Allow the fuel to cool down before opening any line connections otherwise there is a danger of scalding.
• Wear protective gloves.
• Wear safety glasses.
- Disconnect the fuel line couplings - A and B - and remove the fuel lines.
- Remove the fuel filter housing and set it aside.
- Disconnect the connector from the differential pressure sensor - 2 -.
- Remove the bolts - 1 -.
- Lay the differential pressure sensor and mount on the particulate filter.
- Open the clips - arrows - and remove the toothed belt guard.
- Remove the rear part of the 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 - and guards.
- Rotate the engine to Top Dead Center (TDC) and secure the crankshaft toothed belt gear using the crankshaft stop (T10050).
- The crankshaft stop can be pushed from the front side of the toothed belt gear onto the crankshaft toothed belt gear splines - 2 -. The toothed segment must be at 12 o'clock.
• The marks on the crankshaft toothed belt gear - 2 - and the crankshaft stop (T10050) - 1 - must align.
- The pin - arrow - on the crankshaft stop (T10050) must rest in the opening in the sealing flange.
- Mark the rotation direction of the toothed belt.
- Loosen the camshaft sprocket bolts - 1 -.
- Loosen the high pressure pump toothed belt gear bolts - 2 -.
- Loosen the tensioning roller nut - 1 -.
- Turn the tensioning roller eccentric pulley using the special wrench, long reach (T10264) counterclockwise - arrow - until the tensioning roller can be locked with the locking tool (T10265).
- Turn the tensioning roller eccentric pulley clockwise - arrow - all the way and tighten the nut - 1 - by hand.
- Remove the toothed belt from the idler roller and then from the remaining toothed belt gears.
Installing
• The toothed belt may be adjusted only when the engine is cold because the position of the pointer on the tensioning roller will change due to the temperature of the engine.
• The engine mount bracket must be removed in order to replace the tensioning roller. Refer to => [ Engine Mount and Bracket ] Engine Mount and Bracket.
• Replace the bolts for the camshaft and high pressure pump pulleys.
• There are 2 versions of the tensioning roller that can be installed. It is possible to exchange them for one another. When adjusting, first check which tensioning roller is installed.
• The locking tool (T10265) must be inserted in the tensioning roller and the roller must be secured on the right stop.
• Secure the crankshaft with the crankshaft stop (T10050).
• Turn the camshaft hub with 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.
- Lock the camshaft hub with 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 bolt(s), which was tightened hand tight.
• Rotate the high pressure pump hub with a screwdriver at the bolt heads until it can be secured.
Positioning the High Pressure Pump Hub
- Secure the high pressure pump hub with the diesel injection pump locking pin (3359). To do that, slide the pin into the hole outside of the toothed belt gear.
- Rotate the camshaft sprocket and high pressure toothed belt gear clockwise in their slots as far as the stop.
- Install the toothed belt on the crankshaft gear, the idler roller, the camshaft sprocket, coolant pump toothed belt gear and the high pressure pump toothed belt gear.
- Lay the toothed belt on the tensioning roller last.
- Loosen the tensioning roller nut and remove the locking tool (T10265).
• Make sure the tensioning roller is properly positioned in the rear toothed belt guard - arrow -.
Tensioning Roller Position Inside the Cylinder Head
- Carefully turn the tensioning roller eccentric pulley using the special wrench, long reach (T10264) clockwise. The pointer - 2 - must be somewhat above the center of the gap in the base plate. This will be corrected when pre-tensioning.
Make sure that the nut - 1 - does not turn with it.
- Hold the tensioning roller in this position and tighten the tensioning roller nut.
- Attach the counterhold tool (T10172) as shown. Push the counterhold tool (T10172) in the - direction of the arrow - and hold the camshaft sprocket pre-tensioned.
- Tighten the bolts for the camshaft sprocket and for the high pressure pump toothed belt gear hand tight.
- Tighten the bolts to 20 Nm.
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft 2 revolutions further in engine rotation direction and just up to TDC for cylinder 1.
- Insert the crankshaft stop (T10050) back into the crankshaft toothed belt gear.
- Rotate the crankshaft in engine rotation direction, until the pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
• In the following check, only the camshaft and crankshaft are secured. The peg position for the high pressure pump hub is very difficult to find again. 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).
• The pointer on the tensioning roller points to the center or a maximum 5 mm to the right of the gap in the base plate.
If the camshaft hub cannot be secured:
- Pull the crankshaft stop (T10050) toward the back until the pin exits the hole.
- Rotate the crankshaft opposite the engine rotation direction just past TDC.
- Slowly turn the crankshaft in engine rotation direction until the camshaft hub is 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 pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
- Tighten the bolts for the camshaft toothed belt gear hand tight.
- Then tighten them to 20 Nm.
If the crankshaft stop (T10050) tab is to the right of the hole:
- Rotate the crankshaft just a little, opposite the engine rotation direction.
- Rotate the crankshaft in engine rotation direction, until the pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
- Tighten the bolts for the camshaft toothed belt gear hand tight.
- Then tighten them to 20 Nm.
Continuation:
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft 2 revolutions further in engine rotation direction and just up to TDC for cylinder 1.
- Check again.
- Now, it is possible to install the camshaft hub. Tighten the bolts as follows:
• Counter hold using the counterhold tool (T10172) and adapter (T10172/4).
• Tighten the bolts to 20 Nm.
• Camshaft sprocket: Tighten an additional 45° (18) turn.
• High pressure pump: Tighten an additional 90° (1/4) turn.
- Install the lower and center toothed belt guard.
- Install the vibration damper.
- Install the ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Install the upper toothed belt guard.
Further installation is in the reverse order of removal. When doing this note the following:
• Make sure the fuel hoses are secure.
• Do not interchange the supply and return lines (the return line is blue or with a blue mark, the supply line is white).
- Install the right front wheel housing liner..
- Install the noise insulation.
Tightening Specifications
Tensioning Roller B
Removing
• The toothed belt may be adjusted only when the engine is cold because the position of the pointer on the tensioning roller will change due to the temperature of the engine.
A used toothed belt could be destroyed if the running direction is reversed.
• Before removing the toothed belt, mark the running direction with chalk or a felt tip pen for reinstallation later.
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
- Remove the noise insulation.
- Remove the coolant expansion tank bolts - 3 -.
- Disconnect and remove the connector from the coolant expansion tank - 2 -.
- Set the coolant expansion tank - 2 - aside.
Very hot fuel can burn your skin.
• The temperature of the fuel lines and may reach 100 °C (212 °F) after stopping the engine. Allow the fuel to cool down before opening any line connections otherwise there is a danger of scalding.
• Wear protective gloves.
• Wear safety glasses.
- Disconnect the fuel line couplings - A and B - and remove the fuel lines.
- Remove the fuel filter housing and set it aside.
- Disconnect the connector from the differential pressure sensor - 2 -.
- Remove the bolts - 1 -.
- Lay the differential pressure sensor and mount on the particulate filter.
- Open the clips - arrows - and remove the toothed belt guard.
- Remove the rear part of the 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 - and guards.
- Rotate the engine to Top Dead Center (TDC) and secure the crankshaft toothed belt gear using the crankshaft stop (T10050).
- The crankshaft stop can be pushed from the front side of the toothed belt gear onto the crankshaft toothed belt gear splines - 2 -. The toothed segment must be at 12 o'clock.
• The marks on the crankshaft toothed belt gear - 2 - and the crankshaft stop (T10050) - 1 - must align.
- The pin - arrow - on the crankshaft stop (T10050) must rest in the hole in the sealing flange.
- Mark the rotation direction of the toothed belt.
- Loosen the camshaft sprocket bolts - 1 -.
- Loosen the high pressure pump toothed belt gear bolts - 2 -.
- Loosen the tensioning roller nut - 1 -.
- Turn the tensioning roller eccentric pulley - 2 - using the special wrench, long reach SW 8 (T10409) clockwise - arrow - until the tensioning roller is free of tension.
- Tighten the nut - 1 - by hand.
- Remove the toothed belt from the idler roller and then from the remaining toothed belt gears.
Installing
• The toothed belt may be adjusted only when the engine is cold because the position of the pointer on the tensioning roller will change due to the temperature of the engine.
• The engine mount bracket must be removed in order to replace the tensioning roller. Refer to => [ Engine Mount and Bracket ] Engine Mount and Bracket.
• Replace the bolts for the camshaft and high pressure pump pulleys.
• There are 2 versions of the tensioning roller that can be installed. It is possible to exchange them for one another. When adjusting, first check which tensioning roller is installed.
• Secure the crankshaft with the crankshaft stop (T10050).
• Rotate the camshaft hub with 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.
- Lock the camshaft hub with 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 bolt(s), which were tightened hand tight.
• Rotate the high pressure pump hub with a screwdriver at the bolt heads until it can be secured.
Positioning the High Pressure Pump Hub
- Secure the high pressure pump hub with the diesel injection pump locking pin (3359). To do that, slide the pin into the hole outside the toothed belt gear.
- Rotate the camshaft sprocket and high pressure toothed belt gear clockwise in their slots as far as the stop.
- Install the toothed belt on the crankshaft gear, the idler roller, the camshaft sprocket, coolant pump toothed belt gear and the high pressure pump toothed belt gear.
- Lay the toothed belt on the tensioning roller last.
- Loosen the tensioning roller nut.
- Carefully turn the tensioning roller eccentric pulley - 2 - with the special wrench, long reach SW 8 (T10409) counterclockwise in the - direction of the arrow -. The pointer - 4 - must be somewhat above the center of the gap in the base plate - 3 -. This will be corrected when pre-tensioning.
Make sure that the nut - 1 - does not turn with it.
The marks on the tensioner and the tensioning roller - arrow - are now closer in the cover.
- Hold the tensioning roller in this position and tighten the tensioning roller nut.
- Attach the counterhold tool (T10172) as shown. Push the counterhold tool (T10172) in the - direction of the arrow - and hold the camshaft sprocket pre-tensioned.
- Tighten the bolts for the camshaft sprocket and for the high pressure pump toothed belt gear hand tight.
- Tighten the bolts to 20 Nm.
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft 2 revolutions further in engine rotation direction and just up to TDC for cylinder 1.
- Insert the crankshaft stop (T10050) back into the crankshaft toothed belt gear.
- Rotate the crankshaft in engine rotation direction, until the pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
• In the following check, only the camshaft and crankshaft are secured. The peg position for the high pressure pump hub is very difficult to find again. A small deviation - arrow - does not affect engine operation.
- Check if:
• The camshaft hub can be secured with the diesel injection pump locking pin (3359).
• The pointer on the tension roller point to the center or maximum 5 mm to the right of the gap in the base plate.
If the camshaft hub cannot be secured:
- Pull the crankshaft stop (T10050) toward the back until the pin opens the hole.
- Turn the crankshaft opposite the direction of engine rotation just past TDC.
- Slowing turn the crankshaft in the direction of engine rotation until the camshaft hub is 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 pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
- Tighten the bolts for the camshaft toothed belt gear hand tight.
- Then tighten them to 20 Nm.
If the crankshaft stop (T10050) tab is to the right of the hole:
- Rotate the crankshaft just a little in the opposite direction of engine rotation direction.
- Rotate the crankshaft in engine rotation direction, until the pin - arrow - on the crankshaft stop fits into the hole in the sealing flange.
- Tighten the bolts for the camshaft toothed belt gear hand tight.
- Then tighten them to 20 Nm.
Continuation
- Remove the diesel injection pump locking pin (3359) and the crankshaft stop (T10050).
- Rotate the crankshaft 2 revolutions further in engine rotation direction and just up to TDC for cylinder 1.
- Check again.
Now it is possible to install the camshaft hub. Tighten the bolts as follows:
• Counter hold with the counterhold tool (T10172) and adapter (T10172/4).
• Tighten the bolts to 20 Nm.
• Camshaft sprocket: Tighten an additional 45° (1/8) additional turn.
• High pressure pump: Tighten an additional 90° (1/4) additional turn.
- Install the lower and center toothed belt guard.
- Install the vibration damper.
- Install the ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Install the upper toothed belt guard.
Further installation is in the reverse order of removal. When doing this note the following:
• Make sure the fuel hoses are secure.
• Do not interchange the supply and return lines (the return line is blue or with a blue mark, the supply line is white).
- Install the right front wheel housing liner..
- Install the noise insulation.
Tightening Specifications
