Camshaft Seal/Variable Valve Timing (VVT) Unit, Replacing
Camshaft seal/variable valve timing (VVT) unit, replacingSpecial tools: 999 5452, 999 5651, 999 5719, 999 5718, 999 5474, 999 5451, 999 5919, 999 5450
Removal
Note: As the illustrations in this service information are used for different model years and/or models, some variation may occur. However, the essential information is always correct.
Removing the camshaft seal
Caution: There are a number of versions of the variable valve timing unit. Therefore it is extremely important to always read the information referring to the engine variant/model year to be remedied.
Note: Crankshaft and camshafts must not be turned more than is stated in the method description!
If the shafts are turned in any other way the valves may be damaged.
Remove:
- the cable from the battery negative terminal.
First read Note when disconnecting/connecting the battery lead.
- the cross stay between the suspension turrets
- the intake pipe between the air cleaner (ACL) and the front cover plate
- air cleaner (ACL) assembly
- the air intake hose for the turbocharger (TC) from the air cleaner (ACL) cover
- the charge air pipe over the engine. Seal the openings
- the upper timing belt cover
- the cover over the ignition coils
- the upper and lower engine stabilizer brace
- the camshaft position (CMP) sensor housing and trigger wheels
- the servo reservoir and the expansion tank. Lift them up and place them on top of the engine
- the front timing belt cover.
Aligning the engine according to the marking
Raise the car.
Remove:
- the right front wheel
- the nuts for the cover in the fender liner.
Install the upper timing belt cover.
Turn the crankshaft clockwise until the markings on the crankshaft and camshaft pulley correspond.
Turn the crankshaft a further 1/4 of a turn clockwise, then back counter-clockwise until the markings correspond.
The markings are illustrated.
Remove the upper timing belt cover.
Removing the timing belt
Remove:
- the belt tensioner
- the center screw for the belt tensioner slightly.
Hold the center screw still. Turn the tensioner eccentric clockwise to 10 o'clock using a 6 mm Allen key.
Remove the timing belt from the camshaft pulleys.
Removing the timing gear pulley with the variable valve timing unit
Install camshaft adjustment tool 999 5452 at the rear of the camshafts.
Screw the adjustment tool sections together into one.
Remove:
- the center plugs for the variable valve timing units (Tx55)
- the center screws for the variable valve timing units (Tx55). Pull or work off the variable valve timing units and timing gear pulleys.
Removing the front camshaft seal
Carefully press in tool 999 5651 between the sealing ring and the camshaft.
Carefully pry out the seal.
Installation
Note: For tightening torques, See Specifications.
Cleaning
Note: When cleaning work around the shaft journal, not in and out. It is essential that any residue from the emery cloth and any other contaminants are completely removed before the new sealing ring is installed.
Use emery cloth 951 1024 to clean the shaft journal and mating surface.
Installing the front camshaft seal
Lubricate the surface of the seal that the camshaft rotates against.
Install the camshaft seal. Use drift 999 5718. Use the mounting screws for the variable valve timing unit. Tighten until the drift bottoms out.
Installing the crankshaft adjustment tool
Remove the starter motor mounting screws.
Pull out the starter motor and put to one side.
Remove the blind cover plug from the hole for the adjustment tool.
Turn the crankshaft clockwise slightly.
Install adjustment tool 999 5451. Ensure that the tool bottoms out against the cylinder block.
Aligning the crankshaft
Turn the crankshaft counter-clockwise until it stops against the adjustment tool.
Check that the marking on the crankshaft timing gear pulley corresponds with the marking on the oil pump.
Installing the variable valve timing (VVT) unit on the exhaust camshaft
Note: The purpose of the "Installing the VVT unit/timing gear pulley" section described here is to ensure that the VVT unit is correctly positioned and to reset the camshaft timing gear pulley to the correct position using the markings made at the factory. This is to ensure that the conditions are correct for any later fault-tracing.
Slacken off, but do not remove, the screws which secure the timing gear pulley to the variable valve timing unit.
Press the timing gear pulley and variable valve timing (VVT) unit on to the camshaft.
Install the center screw which secures the variable valve timing unit to the camshaft. Tighten slightly.
Turn the variable valve timing unit counterclockwise as far as it will go.
Remove the center screw.
Position the upper timing cover.
Turn the timing gear pulley clockwise until the screws at the oval holes are in the limit position.
Continue turning clockwise until the timing gear pulley marking is 1 tooth before the marking on the upper timing cover.
Note: Do not turn counter clockwise during this procedure.
Check that the timing gear pulley is still in the limit position in the oval holes.
Tighten the center screw in the VVT unit. See Specifications.
Check that the variable valve timing unit does not rotate when tightening.
Tighten the center plug. See Specifications.
Turn the variable valve timing unit clockwise to the limit position.
Turn the timing gear pulley so that the markings correspond.
Installing the variable valve timing (VVT) unit on the intake camshaft
Slacken off, but do not remove the screws which secure the timing gear pulley to the VVT unit.
Press the variable valve timing unit / timing gear onto the camshaft.
Install the center screw which secures the variable valve timing unit to the camshaft. Tighten slightly.
Turn the variable valve timing unit counterclockwise as far as it will go. Remove the center screw.
Position the upper timing cover.
Turn the timing gear pulley clockwise until the screws at the oval holes are in the limit position.
Continue turning clockwise until the timing gear pulley marking is 1 1/2 cogs before the marking on the upper timing cover.
Note: Do not turn counter clockwise during this procedure.
Check that the timing gear pulley is still in the limit position in the oval holes. Tighten the center screw in the VVT unit. See Specifications.
Check that the variable valve timing unit does not rotate when tightening. Install and tighten the center plug. See Specifications.
Turn the variable valve timing unit clockwise to the limit position.
Turn the timing gear pulley so that the markings correspond. Remove the upper timing belt cover.
Finishing
Tighten the center screw for the timing belt tensioner. Tighten to 5 Nm.
Installing the timing belt
Install the belt in the following order:
- crankshaft
- the idler pulley
- intake cam pulley
- exhaust cam pulley
- water pump
- tension pulley.
Note: The variable valve timing units does not have a return spring and is easily dislodged when reinstalling the timing belt. Check that the markings correspond.
Adjusting the timing belt
This adjustment is always carried out on a cold engine. A suitable temperature is approximately 20°C/68°F.
At higher temperatures (with the engine at operating temperature or a high outside temperature for example) the indicator is further to the right.
The illustration shows the position of the indicator when aligning the timing belt tensioner at different temperatures.
Hold the center screw secure and turn the belt tensioner eccentric clockwise until the tensioner indicator passes the marked position and reaches the limit position.
Tighten the 3 screws on the timing gear pulley for the exhaust camshaft. Tighten. See Specifications.
Tighten the 3 screws on the intake camshaft timing gear pulley. Tighten. See Specifications.
Note: Check that the variable valve timing units are in the limit position.
Turn the eccentric back so that the indicator reaches the marked position in the center of the window. Remember to hold the center screw secure at the same time.
Hold the eccentric secure. Tighten the center screw. See Specifications. Check that the indicator is in the correct position.
Remove:
- the camshaft adjustment tools
- the crankshaft stop. Install the plug with a new sealing washer. Tighten according to Tightening torque.
Checking the markings and belt tension
Press the toothed belt to check that the indicator on the tensioner moves easily.
Position the upper timing cover.
Turn the crankshaft 2 rotations and check that the markings on the crankshaft and camshaft pulleys correspond.
Turn the crankshaft 2 rotations and check that the markings on the crankshaft and camshaft pulleys correspond.
Check that the indicator on the belt tensioner is within the marked position.
Remove the upper timing cover.
Installing components
Install:
- the trigger wheel. Tighten the screw
- the camshaft position (CMP) sensor housing. Tighten the screws
- the lower and upper torque rod bracket on the cylinder head. Tighten. See Specifications
Install:
- the front timing belt cover
- the cover over the ignition coils
- the upper timing belt cover
- the auxiliaries belt
- the expansion tank
- the servo reservoir. Check that the hoses are correctly positioned
- the starter motor. Tighten the screws at the transmission unit. See Specifications.
Install:
- the intake air hose between the turbocharger (TC) and the air cleaner (ACL) cover
- air cleaner (ACL) assembly
- the intake pipe between the air cleaner (ACL) and the front cover plate
- the charge air pipe above the engine. Remove Rear camshaft seal the seals
- the engine stabilizer brace
- the cable to the battery negative terminal. First read Note when disconnecting/connecting the battery lead.
Checking the engine
Test drive the car to check the function of the engine.
Removing the rear camshaft seal
Remove:
- the cross stay between the suspension turrets
- the air hose from the air cleaner (ACL) to the turbocharger (TC). Place to one side. Seal the openings
- the intake pipe between the air cleaner (ACL) and the front cover plate
- air cleaner (ACL) assembly
- the charge air pipe over the engine. Seal the openings
- the cover over the ignition coils
- the upper and lower engine stabilizer brace
- the camshaft position sensor (CMP) housing and trigger wheel.
Removing the rear camshaft seal
Pull out the seal. Use puller 999 5919.
Use emery cloth 951 1024 to clean the shaft journal and mating surface
Note: When cleaning work around the shaft journal, not in and out. It is essential that any residue from the emery cloth and any other contaminants are completely removed before the new sealing ring is installed.
Lubricate the surface of the seal that the camshaft rotates against.
Install the camshaft seal. Use drift 999 5450.
Note: The seal is normally positioned at the same level as the internally beveled edge. If the shaft journal is showing signs of wear, the seal can be pressed in a further 2 mm: Turn the drift socket.
Installing components
Install:
- the trigger wheel. Tighten the screw
- the camshaft position (CMP) sensor housing. Tighten the screws
- the upper and lower engine stabilizer brace
- the cover over the ignition coils
- the charge air pipe over the engine. Remove the seals
- the intake air hose and air cleaner (ACL)
- the intake pipe between the air cleaner (ACL) and the front cover plate
- the engine stabilizer brace. Tighten the screws at the suspension turrets and the screw for the engine bracket. Check the engine compartment. Wipe the engine compartment clean.