Remove/install cylinder head

AR01.30-P-5800MRT

Remove/install cylinder head

30.03.2020

Engine

256.9 in model 222

Modification notes

23.08.2019

Note added.

Operation step 17

27.02.2020

Screw, cylinder head to crankcase/timing case

BA01.30-P-1004-01MRT

1

Cylinder head

5

Bracket

2

Support plate

6

Chain tensioner

3

Coolant feed pipe

7

Timing chain

4

Screw

8

Gear

1

Cylinder head

10

Cylinder head bolts

9

Bolts

 Caution

Risk of injury to skin and eyes due to handling of engine oil. Risk of poisoning caused by swallowing engine oil

Wear protective gloves, protective clothing and safety glasses.
Do not fill engine oil into beverage containers.

AS18.00-Z-0001-01A

 Warning

Risk of injury to skin and eyes suffering scalding from contact with hot coolantspray. Risk of poisoning from swallowing coolant.

Do not open cooling system unless coolant temperature is below 90 °C. Open cap slowly and release the pressure. Do not pour coolant into beverage containers.
Wear protective gloves, protective clothing and safety glasses.

AS20.00-Z-0001-01A

Topical note

Notes on threaded connections fastened using a tightening angle-based tightening process

AH00.00-P-0020-01A

Topical note

Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A

 

Remove/install

1

Remove camshaft housing.

AR05.20-P-6997MRT

2

Remove exhaust gas turbocharger with exhaust manifold.

AR09.40-P-6036MRT

3

Remove coolant return flow line for exhaust gas turbocharger.

AR20.20-P-1050MRT

4

Release and disconnect electrical connector of coolant temperature sensor (B11/4).

5

Remove bracket (5) from cylinder head.

 Screw, electrical connector bracket to cylinder head

*BA15.18-P-1004-01MRT

6

Remove support plate (2).

 Screw, shield to fuel high-pressure pump housing/support plate

*BA07.02-P-1006-01MRT

 Screw, support plate above fuel high-pressure pump to cylinder head

*BA07.02-P-1004-01MRT

7

Remove coolant feed pipe (3).

 Installation: Replace O-ring.

 Screw, coolant feed pipe to cylinder head/crankcase

*BA20.20-P-1001-02MRT

8

Remove screw (4).

 Screw/bolt, thermostat coolant connection pipe to cylinder head

*BA01.30-P-1010-01MRT

9

Remove low pressure fuel line from lifting eye.

 Bolt, holder for low-pressure line to lifting eye/crankcase/timing case cover

*BA07.03-P-1008-01MRT

 Bolt, holder for low-pressure line to shield/supporting plate

*BA07.03-P-1007-01MRT

10

Remove spark plugs.



AP15.10-P-1580E

11

Remove chain tensioner (6).

AR05.10-P-7800MRT

12

Secure timing chain (7) against falling down.

13

Remove gearwheel (8).

AR05.10-P-7760MRT

14

Remove top slide rail.

AR05.10-P-8421MRT

15

Remove screws (9) in reverse order of the tightening procedure.

Tightening procedure for cylinder head bolts

AR01.30-P-5800-01MRT

 Installation: Observe tightening procedure.

 Screw, cylinder head to crankcase/timing case

*BA01.30-P-1004-01MRT

16

Remove cylinder head bolts (10) in reverse order of the tightening procedure.

Tightening procedure for cylinder head bolts

AR01.30-P-5800-01MRT

 Installation: Observe tightening procedure.

 Screw, cylinder head to crankcase/timing case

*BA01.30-P-1004-01MRT

17

Remove cylinder head (1).

General information on checking valves, valve seats and valve guides

AH05.30-P-1000-02SZ

 Aid of helper required.

18

Remove cylinder head gasket.

 Installation: Replace cylinder head gasket.

19

Remove hydraulic valve play compensation elements.

AR05.00-P-2013MRT

20

Remove valves.

When replacing the cylinder head (1).

AR05.30-P-3511MRT

21

Remove exhaust manifold clamping strips.

When replacing the cylinder head (1).

Tightening pattern for turbocharger

AR09.40-P-6020-10MRT

 Screw, exhaust manifold (exhaust gas turbocharger) strip clamp to cylinder head

*BA14.10-P-1002-02MRT

22

Remove coolant temperature sensor (B11/4).

When replacing the cylinder head (1).

AR15.60-P-2712MRT

23

Remove lifting eyes.

When replacing the cylinder head (1).

 Bolt, lifting eye to cylinder head

*BA01.30-P-1009-01MRT



Clean

24

Clean sealing surfaces on cylinder head (1), timing case cover, and crankcase.


Do not use any sharp-edged tools or abrasive paper.
Sealing surfaces will otherwise be damaged.

Loctite 7063 (400 ml) cleaning spray

*BR00.45-Z-1046-04A

Loctite 7200

*BR00.45-Z-1038-04A

25

Cover threaded holes of the cylinder head bolts (10) and screws (9) in the crankcase with rags and blow out with compressed air.



Check

26

Check sealing surfaces of the cylinder head (1), timing case cover, and crankcase for cracks and unevenness.


Do not rework cylinder head (1) and crankcase (surface grinding).
The permissible production tolerances will otherwise be exceeded.

 Tightening of the cylinder head bolts (10) compensates a slight distortion of the cylinder head (1) in the longitudinal or transverse direction.

If cracks or unevenness are present,



replace cylinder head (1), timing case cover,and crankcase.

Crankcase

AR01.10-P-2500MRT

Timing case cover

AR01.40-P-8000MRT

27

Check cylinder head bolts (10).

AR01.30-P-5800-03MRT

Cylinder head bolt

*BE01.30-P-1001-04B

28

Install in the reverse order.

29

Change engine oil and oil filter element.



AP18.00-P-0101MRT

Cylinder head/cylinder head bolts

Number

Designation

Engine 256

BE01.30-P-1001-04B

Cylinder head bolt

Thread diameter

M

11

Length (L) when new

mm

158 0,5

Length (L)

mm

159,5

For picture, see

-

 Cylinder head

Number

Designation

Engine 256.9

BA01.30-P-1004-01MRT

Screw, cylinder head to crankcase/timing case

M8

Nm

20

M11

Stage 1

Nm

10

Stage 2

Nm

40

Stage 3

°

90

Stage 4

°

90

Stage 5

°

90

 Cylinder head

Number

Designation

Engine 256.9

BA01.30-P-1009-01MRT

Bolt, lifting eye to cylinder head

Nm

29

 Cylinder head

Number

Designation

Engine 256.9

BA01.30-P-1010-01MRT

Screw/bolt, thermostat coolant connection pipe to cylinder head

Nm

8

 High pressure fuel pump, high pressure fuel pump housing

Number

Designation

Engine 256.9

BA07.02-P-1004-01MRT

Screw, support plate above fuel high-pressure pump to cylinder head

Nm

8

 High pressure fuel pump, high pressure fuel pump housing

Number

Designation

Engine 256.9

BA07.02-P-1006-01MRT

Screw, shield to fuel high-pressure pump housing/support plate

Nm

8

 High-pressure line, low-pressure line, fuel distributor

Number

Designation

Engine 256.9

BA07.03-P-1007-01MRT

Bolt, holder for low-pressure line to shield/supporting plate

Nm

8

 High-pressure line, low-pressure line, fuel distributor

Number

Designation

Engine 256.9

BA07.03-P-1008-01MRT

Bolt, holder for low-pressure line to lifting eye/crankcase/timing case cover

Nm

8

 Exhaust manifold

Number

Designation

Engine 256.9

BA14.10-P-1002-02MRT

Screw, exhaust manifold (exhaust gas turbocharger) strip clamp to cylinder head

Nm

20

 12 V on-board electrical system engine wiring harness

Number

Designation

Engine 256

BA15.18-P-1004-01MRT

Screw, electrical connector bracket to cylinder head

Nm

8

 Engine radiator, coolant hoses and lines

Number

Designation

Engine 256

BA20.20-P-1001-02MRT

Screw, coolant feed pipe to cylinder head/crankcase

Nm

8

Repair materials

Number

Designation

Order number

BR00.45-Z-1038-04A

Loctite 7200

Henkel AG & Co. KGaA
http://www.loctite.de

BR00.45-Z-1046-04A

Loctite 7063 (400 ml) cleaning spray

A 001 986 71 71 09