Chain Tensioner
WM 153619 Removing and installing chain tensioner on 4.8-liter DFI engines
Preliminary work
Preliminary work
1. Remove air-cleaner cover and air-cleaner element on the right side.
Information
Installation position and overview of functions
Timing chain and chain guide
1 - Threaded peg - Tightening torque: 35 Nm (26 ftlb.)
2 - Threaded peg - Tightening torque: 20 Nm (15 ftlb.)
3 - Guide rail
4 - Tensioning rail
5 - Chain tensioner with seal - Tightening torque: 60 Nm (44 ftlb.)
6 - Pin (for locking the oil-pump tensioning rail)
A - Direction of travel
Chain tensioner, sealing flange
1 - Joint flange (oil sealing lip with engine oil); align with sleeve or vibration balancer
2 - Screw, M6 x 12 - Tightening torque: 10 Nm (7.5 ftlb.)
3 - Screw, M6 x 50 - Tightening torque: 10 Nm (7.5 ftlb.)
4 - Sealing ring on chain tensioner
5 - Chain tensioner - Tightening torque: 60 Nm (44 ftlb.)
Removing chain tensioner
Removing chain tensioner
Make sure the vehicle cannot start. To do this, switch off ignition and remove ignition key.
1. Make room for removing the chain tensioner by loosening the wire harness.
1.1. Open the retaining clip -3- (-arrow B-) and remove the B+ line -4- (-arrow C-).
Wire harness on generator
2. Disconnect plug connection for generator.
2.1. Release plug connection for generator-1- (-arrow A-) and disconnect it -arrow B-.
2.2. Pull plug connection for generator -1- along with the line bracket off the B+ line -arrow C-.
Disconnecting plug connection for generator
Caution:
Risk of damage to timing drive mechanism!
Never twist the crankshaft against the direction of rotation.
Never twist the crankshaft when the chain tensioner is removed.
- Forces from the valve drive can cause the timing chain to jump over or tilt.
Information:
The chain tensioner can be removed in any timing chain position.
The timing chain cannot by dislodged by removing the chain tensioner (screw securing timing chain in place).
The crankshaft and camshafts must not be turned when the chain tensioner is removed.
3. Carefully unscrew chain tensioner. -5- The chain tensioner is made of aluminum. Check the thread for signs of damage. Clean the thread if there is slight abrasion. Replace sealing ring.
Installation position of chain tensioner in timing-case cover
Installing chain tensioner
Installing chain tensioner
Caution:
Risk of damage to timing drive mechanism!
Never twist the crankshaft against the direction of rotation.
Never twist the crankshaft when the chain tensioner is removed.
- Forces from the valve drive can cause the timing chain to jump over or tilt.
Information:
The chain tensioner can be removed in any timing chain position.
The timing chain cannot by dislodged by removing the chain tensioner (screw securing timing chain in place).
The crankshaft and camshafts must not be turned when the chain tensioner is removed.
1. The chain tensioner is made of aluminum. Check the thread for signs of damage. Clean the thread if there is slight abrasion.
Information:
If the chain tensioner is removed, the aluminum sealing ring must be replaced.
2. Carefully screw chain tensioner in as far as possible with your hand. -5- Tighten chain tensioner. Tightening torque: 60 Nm (44 ftlb.)
3. Check crankshaft by turning it two turns in a clockwise direction. Make sure that it turns easily.
Installation position of chain tensioner in timing-case cover
4. Connect plug connection for generator.
4.1. Clip in plug connection for generator -1- along with the line bracket on the B+ line -arrow A-.
4.2. Connect plug connection for the generator -1- (-arrow B-) until it engages securely -1-.
Connecting plug connection for generator
5. Fit wire harness in front of the chain tensioner.
5.1. Insert B+ line -4- into the retaining clip -3- (-arrow B-) and close the retaining clip -3- (-arrow C-).
Installing heat shield for generator lines
Subsequent work
Subsequent work
1. Fit air-cleaner cover and air-cleaner element on the right side.