Remove/install cylinder head cover

AR01.20-P-5014MT

Remove/install cylinder head cover

18.02.2020

Engine

270 in model 117, 156, 176, 242, 246.2

Modification notes

19.08.2019

Note added.

Operation steps 20 and 26

1

Cylinder head cover

1s

Bolts

2

Cylinder head

3

High pressure pump

8

Filler neck

12

Guide tube

4

Rail

9

Vacuum line

13

Engine suspension lugs

5

Air intake pipe

10

Vacuum line

14

Bracket

6

Vacuum pump

11

Coolant vent line

T1

Ignition coils

7

Engine wiring harness

 

Remove/install

1

Remove ground line from the battery.

AR54.10-P-0003NKB

2

Mount engine support fixture.

AR33.10-P-0105NKB

3

Drain off coolant.

AR20.00-P-1142NKB

4

Remove high-pressure pump (3).

AR07.02-P-1020MT

5

Remove rail (4).

AR07.03-P-1010MT

6

Remove front cover.

AR01.30-P-5700MT

7

Remove air intake pipe (5).

Engine 270 in model 117, 156
with code 494 (US version)

AR09.10-P-8131MTU

Engine 270 in model 117, 156, 176, 242, 246.2
except code 494 (US version)

AR09.10-P-8131MT

8

Remove ignition coils (T1).

AR15.12-P-2003MT

9

Remove vacuum pump (6).

AR43.05-P-1320MT

10

Remove engine wiring harness (7) from the cylinder head cover (1).

AR01.00-P-2410-02MT

11

Remove filler neck (8) and place to one side with the bleed line.

 Replace seal.

 Bolt, filler neck to cylinder head cover

*BA01.20-P-1003-01R

12

Detach vacuum line (9) from the vacuum cell of the exhaust gas turbocharger.

13

Detach vacuum line (10) from the switchover valve of the coolant pump.

14

Disconnect vacuum lines (9, 10) from each other and place to one side.

15

Remove coolant bleed line (11) from the cylinder head cover (1) and place to one side.

16

Remove guide tube (12) from the cylinder head cover (1) and swivel to one side.

17

Remove engine lifting lugs (13).

 Bolt, lifting eye at front right to cylinder head

*BA01.30-P-1005-01Y

 Bolt, lifting eye at the rear left to cylinder head/cylinder head cover

*BA01.30-P-1006-01Y

 Bolt, lifting eye at rear right to cylinder head/cylinder head cover

*BA01.30-P-1007-01Y

18

Remove cap from the cylinder head cover (1) and cylinder head (2).

 Install new cap.

19

Loosen screw/bolts (1s) for cylinder head cover (1) in the reverse order of the tightening procedure and remove them.

AR01.20-P-5014-03MT

 Installation: Replace screw/bolts (1s) with new ones.

 Screw/bolt, cylinder head cover to cylinder head

*BA01.20-P-1001-01R

20

Carefully pry off cylinder head cover (1) from the cylinder head (2).

Notes on application of flange sealants to seal major assemblies

AH00.00-P-0500-01MNE

Notes on sealant path for cylinder head cover

AH01.30-P-1000-08MM


Do not hammer in a tool to pry off between cylinder head cover (1) and cylinder head (2).
The sealing surfaces can be damaged otherwise. Use puller screw if necessary.

 The cylinder head cover (1) and cylinder head (2) create a unit and can therefore only be exchanged together.

 Installation: Replace sealing ring.

 Installation: Apply sealant to cylinder head cover (1).

Sealant, Loctite 5970, 50 ml

*BR00.45-Z-1013-01A

 Application gun

*112589002500

21

Change bracket (14) of the engine cover.

When installing a new cylinder head cover (1) and cylinder head (2).

22

Change bracket for the air intake pipe (5).

When installing a new cylinder head cover (1) and cylinder head (2).

23

Change Hall sensors of the camshafts.

When installing a new cylinder head cover (1) and cylinder head (2).

AR15.10-P-2000MT

24

Change slide rail.

When installing a new cylinder head cover (1) and cylinder head (2).

AR05.10-P-8480MT



Check

25

Check slide rail of the timing chain for galling and score marks and replace if necessary.

26

Check camshaft mounts in the cylinder head cover (1) and check camshafts for galling and score marks.

General information on checking camshafts and bearing points of camshafts

AH05.20-P-1000-09SZ

If necessary, replace cylinder head cover (1) together with the cylinder head (2) and camshafts,



Replace cylinder head

AR01.30-P-5800MT

Replace camshafts

AR05.20-P-6992MT



Clean

27

Clean sealing surfaces on the cylinder head (2) and cylinder head cover (1).

AR01.00-P-0050-01A


Do not use any sharp-edged tools or abrasive paper.
The sealing surfaces can be damaged otherwise.

Loctite 7200

*BR00.45-Z-1038-04A

Loctite 7063 (400 ml) cleaning spray

*BR00.45-Z-1046-04A

28

Install in the reverse order.

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

29

Perform engine test run and check engine in terms of leak tightness while engine is running.

 Crankcase ventilation system, cylinder head cover, camshaft housing

Number

Designation

Engine 270

BA01.20-P-1001-01R

Screw/bolt, cylinder head cover to cylinder head

Stage 1

Nm

10

Stage 2

°

90

 Crankcase ventilation system, cylinder head cover, camshaft housing

Number

Designation

Engine 270

BA01.20-P-1003-01R

Bolt, filler neck to cylinder head cover

Nm

9

 Cylinder head

Number

Designation

Engine 270

BA01.30-P-1005-01Y

Bolt, lifting eye at front right to cylinder head

M6

Nm

9

M8

Nm

20

 Cylinder head

Number

Designation

Engine 270

BA01.30-P-1006-01Y

Bolt, lifting eye at the rear left to cylinder head/cylinder head cover

M8

Nm

20

 Cylinder head

Number

Designation

Engine 270

BA01.30-P-1007-01Y

Bolt, lifting eye at rear right to cylinder head/cylinder head cover

M8

Nm

20

Repair materials

Number

Designation

Order number

BR00.45-Z-1013-01A

Sealant, Loctite 5970, 50 ml

A 003 989 98 20 10

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