11 12 100Removing and installing cylinder head (M47)

Remove battery cover.

Follow instructions for disconnecting and connecting battery,

refer to General Information MG 12.

Disconnect negative lead from battery.

Caution!

When working on the oil, coolant or fuel circuit, you must protect the alternator against contamination.


Cover alternator with suitable materials.

Failure to comply with this procedure may result in an alternator malfunction.

Disconnect intake air manifold,

refer to 11 61 050.

Remove injection nozzles,

refer to 13 53 320.

Remove cylinder head cover,

refer to 11 12 000.

Unfasten exhaust turbocharger from exhaust manifold.Installation:

Replace seal.

Coat thread with copper paste -CRC-.

Tightening Torque,

refer to Technical Data 11 65 1AZ.


Drain and dispose of coolant,

refer to General Information for working on cooling system.

Installation:

Replace seal.

Tightening Torque,

refer to Technical Data 11 11 5AZ.

Fill cooling system, vent and check for leaks,

refer to 17 00 005.


Remove EGR cooler,

refer to 11 71 100.

Note:

Thermostat for EGR cooler does not have to be removed.


Pull lock (1) and detach water hoses.Installation:

Release screw on coolant connecting line.Note:

Screw with M7 thread.


Installation:

Replace sealing ring.

Install screw and tighten down.

Tightening Torque,

refer to Technical Data 11 51 1AZ.


Disconnect intake pipe from EGR valve.

Unscrew bolt (1).

Pull lock (2) and detach water hose.

Remove coolant connecting line.

Note:

Remove double pipe from cylinder head only, hoses remain connected.


Release double pipe on side of cylinder head.
Release retaining screw (1) for double pipe at rear of cylinder head.Note:

Retaining screw (1) is between the hoses.


Release engine section of wiring harness, remove cable channel from retainer and lay to one side.

Removal:

Removal of cylinder head is described separately from installation. Assembly sequence for removal and installation is different.

Remove camshafts,

refer to 11 31 001.

Caution!
These screws must ”not” be removed.

Remove suspension element from cylinder head.
Remove bearing pin (1) for sliding rail.Note:

The sliding rail is guided and secured at a bearing pin and is only removed later because of better accessibility.


Remove bearing pin (1) for tensioning rail.

Lift out tensioning rail (2) towards top.

Release screw (1) between timing case cover and cylinder head.Note:

Screw (1) is sealed with a sealing ring.


Release screw connection to timing case cover.
Note:

The hydraulic valve clearance compensating elements (HVA) can fall out when the cylinder head is later put down.

If necessary, remove hydraulic valve clearance compensating elements and put down in an orderly fashion.


Unfasten cylinder head bolts from outside to inside in following sequence 10 ... 1.
Caution!
The glow plugs protrude at the sealing face and may be damaged when the cylinder head is put down.

  • Remove cylinder head and put down so that glow plugs are not damaged.
If necessary, remove glow plugs with special tool 11 6 050.Note:

Special tools 11 6 050 delivered before 4/98 should be drilled out at 9.5 mm dia. 20 mm deep.


Installation:

Tightening Torque of glow plugs,

refer to Technical Data 12 23 2AZ.


Remove sliding rail (1) from bearing pin.Note:

The cylinder head is set up without the sliding rail (1) due to better accessibility.

The sliding rail (1) is reinstalled at a later stage.


Remove cylinder head gasket.
Note:
If the engine is cranked with the camshafts or a cylinder head removed, every revolution must be counted exactly so that the TDC firing position and the overlap TDC position of the injection pump are not confused.

Caution!

The chain wheel of the injection pump has ”no” marking for the firing TDC position of the injection pump.

(Ratio of crankshaft to injection pump = 2:1)


Note:

If the engine has been cranked and the TDC firing position of the injection pump is no longer known, it can be determined by way of the adjustment value of the injection pump.


This work instruction need only be carried out if the TDC firing position of the injection pump is no longer known.

The following describes how to look for the firing TDC position of the injection pump.

Lift timing chain and hold under tension.

Crank engine at central bolt until piston of first cylinder is in ”TDC position”.

The plug (1) must be released so that the static basic setting can be measured.Installation:

Replace sealing ring.

Tightening Torque of plug (1),

refer to Technical Data 13 51 12AZ.


Note:

The setting value of the injection pump is stamped next to the nameplate.

The fuel return line (1) covers the injection pump nameplate.


Remove fuel return line (1).Installation:

Replace sealing ring.

Tightening torque of fuel return line (1),

refer to Technical Data 13 51 11AZ.


Screw in special tool 13 5 200 and tighten down by hand.

Install special tool 00 2 510 (dial gauge) and secure to approx. 5 mm preload.

Lift timing chain and hold under tension.

Rotate engine at central bolt 90° against direction of rotation.

Set scale of dial gauge to zero.

Crank engine at central bolt in direction of rotation until piston of first cylinder is in ”TDC position”.

Locate flywheel in TDC position with special tool 11 2 300.

 

Compare setting values next to nameplate and on dial gauge (tolerance ± 0.1 mm).Note:

If the pointer on the dial of the special tool 00 2 510 (dial gauge) has not moved, the injection pump is in the overlap TDC position.

Pull special tool 11 2 300 back until flywheel is no longer secured in position.


Crank engine at central bolt once in direction of rotation until piston is again in TDC position.

The injection pump is now in the firing TDC position.

Note:

If necessary, check setting value of injection pump with special tool 00 2 510 (dial gauge) again.


Installation:

Installation of cylinder head is described separately from removal. The assembly sequence differs between removal and installation.

Clean sealing faces of cylinder head and engine block; if necessary, remove traces of sealing compound with hardwood spatula. While proceeding, make sure that no remnants of sealing compound drop into the oilways and cooling ducts.

Without work on the engine block which changes the piston protrusion, use a new cylinder head gasket with the same thickness marking (number of holes).

If work is carried out on the crank drive or piston, the seal thickness must be redetermined.

Measuring the piston clearance:

Place dial gauge with measuring fixture special tool 00 2 530 on the cleaned cylinder head sealing face and set the preload to zero.

Clean piston at measuring points (1 and 2).

Place dial gauge at measuring point (1) on cleaned piston and determine highest point by rotating crankshaft.

Measure and note down piston protrusion at measuring points (1 and 2) on all 4 pistons.

The highest piston protrusion at the measuring points (1 and 2) of all 4 pistons determines the thickness of the cylinder head gasket.

Piston protrusion up to 0.91 mm

  • Install 1 hole cylinder head gasket.

Piston protrusion 0.92 ... 1.03 mm

  • Install 2 hole cylinder head gasket.

Piston protrusion over 1.03 mm

  • Install 3 hole cylinder head gasket.
Note:

To avoid damaging the valves when the camshafts are later installed, it is necessary to crank the engine to 45° before TDC.

Lift timing chain and hold under tension.

Crank engine at central bolt approx. 45° against direction of rotation.


Check that dowel sleeves are undamaged and correctly located.
Note:

The joints between timing case cover and engine block are sealed with sealing strips that are attached as standard.

It is not necessary to apply a permanently elastic sealing compound.


Caution!

The tapped bores in the engine block must be dirt and oil-free.

(Risk of cracks, incorrect tightening values).


Lay on new cylinder-head seal with previously determined seal thickness (number of holes).

Fit cylinder head and tighten down using new screws (slightly oiled) in sequence 1 ... 10.

Tightening Torque,

refer to Technical Data 11 12 7AZ.

Use special tool 00 9 120 for torsion angle tightening.

Replace sealing ring on screw (1).

Install and tighten down screw (1) between timing case cover and cylinder head.

Install and tighten down screws.
Note:

Shown without cylinder head for purposes of clarity.


The sliding rail (1) is guided below via a bearing pin (2).

Place sliding rail (1) from above against bearing pin (2) and press downwards until rail (1) snaps audibly into place.

Note:

Bearing pin (1) for sliding rail has a coated thread and must be replaced.


Install and secure new bearing pin (1) for sliding rail.

Tightening Torque,

refer to Technical Data 11 31 12AZ.

Insert tensioning rail (2) from above.

Note:

Bearing pin (1) for tensioning rail has a coated thread and must be replaced.


Install and secure new bearing pin (1) for tensioning rail.

Tightening Torque,

refer to Technical Data 11 31 12AZ.

Install camshafts,

refer to 11 31 001.

Assemble engine.

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