Valve Stem Seals, Replace (Cylinder Head Installed)
Notice:
The operation is described for an X 16 XEL engine. For Y 16 XE. Z 16 XE, X 18 XE1, Z 18 XE, Z 18 XEL proceed analogously.
Remove, Disconnect
Remove camshafts - see operation "Camshafts, Remove and Install".
Remove hydraulic valve lifter - see operation "Hydraulic Valve Lifter. Remove and Install".
Detach wiring harness plug for camshaft sensor (2) from bracket.
Unclip wiring harness plug for crankshaft pulse pick-up (3) from bracket.
Detach wiring harness plugs(4) from injectors. Detach wiring loom from fuel distributor pipe.
Important!
Fuel escapes - observe safety measures and national legislation. Connect Fuel Pressure Gauge KM-J-34730-91 to test connection (1) on fuel distributor pipe Reduce fuel pressure by opening valve on fuel pressure gauge Collect escaping fuel in a suitable containerRemove, Disconnect
Unscrew fastening bolts (arrows) for fuel distributor pipe (5). Carefully pull fuel distributor pipe with injectors out of lower part of intake manifold.
Remove, Disconnect
Remove spark plugs with KM-194-E.
install flywheel or drive disc with KM-911 (1) and remove increment disc (2) from toothed belt drive gear.
Required Special Service Tools from Valve Spring Compressor MKM-889:
| Installation Head | MKM-889-2 |
| Thrust piece | MKM-889-3 (identification 6a) |
| Installation Shaft | MKM-889-9 |
| Support | MKM-889-11 |
| Lever Arm | MKM-889-12 |
| Joint | MKM-889-13 |
| Removal Head | MKM-889-15 |
| Pliers | MKM-889-16 |
| Compressed Air Adapter | MKM-889-17 |
Install, Connect
The adjustable supports are to be adjusted in such a manner that the installation shaft is subsequently positioned centrally over the spark plug bores.
Centrally align the support heads (1) on the support feet (2) and secure with the clamp bolt to the underside (arrow).
Place both supports (3) together with installation shatf (4) onto the inner camshaft bearings and lightly tighten with fastening bolts of camshaft bearing shells.
Install, Connect
Align installation shaft by pushing supports onto cylinder head in such a manner that it is secured over the spark plug bores Then fasten both supports with fastening bolts of camshaft bearing shells.
Secure installation shaft against movement and tighten the clamp bolt in support head (1).
Adjust
Set crankshaft to "1st Cylinder TDC" - the line mark on the toothed belt drive gear (2) must align with the mark on the rear toothed belt cover (3).
A second guide mark (4) should be made on the toothed drive belt gear, offset at 180° from the existing "1st cylinder -TDC" mark, to enable precise setting of pistons for cylinders 2 and 3 to "TDC".
For vehicles with manual transmission: Engage 1st gear or, for vehicles with automatic transmission, selector level position "P". Apply parking brake and ensure that the wheels ,are in contact with the ground
Install, Connect
Screw Compressed Air Adapter MKM-889-17 (1) into spark plug thread of 1st cylinder and apply compressed air to cylinder.
Assemble lever arm (2). joint with fastening bolts (4) and removal head (3) assembly.
Slide entire assembly onto installation shaft over the 1st cylinder.
Install, Connect
Compress valve spring of the 1st cylinder successively using lever arm and removal head (arrow)
Important!
The removal head must stand vertically above the valve stem - realign removal head on level arm or supports on cylinder head once again, if necessary.
Remove, Disconnect
Remove valve cotters with Special Pliers MKM-889-16 (1) - do not use magnetic tool to remove the valve cotters.
Remove upper valve head and valve springs.
Important!
Place all removed parts to one side such mat they are not interchanged during re-installation.
Remove, Disconnect
Remove valve stein seal from valve guide with KM-840 (1).
Install, Connect
Push enclosed assembly sleeve (3) onto valve stem and lightly coat with engine oil. Place new valve stem seal (2) onto valve guide using KM-835-A (4) and carefully drive in to stop with light blows. Remove assembly sleeve, insert valve spring and upper valve spring plate.
Install, Connect
The removal head should be replaced by the installation head using the appropriate thrust piece to install the valve cotters.
Assemble
Fit installation head - to do this dismantle installation head which comprises thrust piece mounting (1) and lever mounting (5).
Unscrew closure bolt (4) of thrust piece mounting - Note: Bolt is spring-loaded!
Insert thrust piece (2) together with spring (3) into thrust piece mounting and screw in closure bolt. Screw thrust piece mounting and
Install, Connect
Insert valve cotters into installation head - to do this insert both valve cotters (9) into installation head with grooves towards plastic clamping sleeve.
Secure valve cotters to the thrust piece (8) by sliding the plastic clamping sleeve (6) with the steel retaining clips.
Install, Connect
Place installation head with the thrust piece (1) vertically on the valve stem and depress uniformly with the lever arm - the valve spring will become pretensioned and the valve cotters will be inserted automatically in the correct position on the valve stem.
Inspect
Ensure seating of valve cotters in valve stem is correct.
Important!
Do not perform a 2nd test without checking that both valve cotters are located in the correct installation position in the installation head - if necessary re-insert the valve cotters.
install Connect
The valve stem seals of the fourth cylinder are then replaced as the crankshaft position (1st cylinder TDC = 4th cylinder TDC) can be maintained.
Screw Compressed Air Adapter MKM-889-l7 into spark plug thread of 4th cylinder and apply compressed air to cylinder.
Carry out the procedure on the 4th cylinder analogously.
Install, Connect
Finally me valve stem seals of the 2nd and 3rd cylinders are replaced. To do this, both supports for the automatik valve spring compressor (1) must be repositioned from me inner to the outer camshaft bearings.
,br> Align the installation shaft centrally over the spark plug threads and fasten supports.
Slide the lever arm, joint and removal head assembly onto installation shaft.
ADJUST
Move pistons of 2nd and 3rd cylinders into "TDC position" - turn crankshaft 180* and align guide mark on toothed belt drive gear (2) with mark on rear toothed belt cover (3).
Install, connect
Screw Compressed Air Adapter MKM-889-17 into relevant spark plug thread and apply compressed air to cylinder. Carry out procedure on the 2nd and 3rd cylinders analogously.
Install spark plugs with KM-194-E - tightening torque 25 Nm /18 Ibf. ft.
Install hydraulic valve lifter - see operation "Hydraulic Valve Lifter. Remove and Install".
Install camshafts - see operation "Camshafts, Remove and Install".
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