Check timing chain

AR05.10-S-7600SE

Check timing chain

06.10.2016

Engine

642 in model 639

Modification notes

26.09.2016

Document contents completely revised

Operation steps 1 to 9

1

Measuring chain tensioner

2

Sealing ring



Remove

1

Remove the chain tensioner

AR05.10-S-7800SE



Check

2

Attach a suitable sealing ring (2) at measuring chain tensioner (1)

 The sealing ring (2) is available as a replacement part of the fuel injection system, see EPC Group 07.

 Measuring chain tensioner

*642589036300

3

Install the measuring chain tensioner (1)


Install the measuring chain tensioner (1) without seal.
Otherwise a wrongly measurement value will be determined.

 Measuring chain tensioner to cylinder head

*BA05.10-N-1006-01G

 Measuring chain tensioner

*642589036300

4

Push sealing ring (2) onto the measuring chain tensioner (1) up to the end stop of the scale (see Figure b)

 Danger !

Risk of injury. Moving parts can pinch, crush or, in extreme cases even sever extremities.

No parts of the body or limbs should be within the operating area of mechanical components when moving components.

AS00.00-Z-0009-01A

5

Rotate engine twice at crankshaft twice in direction of engine rotation and determine the greatest indicator value

AR01.00-S-0100SE

 Afterwards the sealing ring (2) remains at the greatest indicator value (see Figure a).

Wear dimension of timing chain stretch

*BE05.10-N-1001-03S

For a reached or exceeded degree of wear of the timing chain stretch



Replace timing chain

AR05.10-S-7601SE

6

Remove the measuring chain tensioner (1)

 Measuring chain tensioner

*642589036300

7

Remove sealing ring (2) from measuring chain tensioner (1)



Install

8

Install the chain tensioner

AR05.10-S-7800SE



Check

 Danger !

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

9

Check leaktightness in the area of the chain tensioner for a running engine

 Visual inspection only.

Timing chain check values

Number

Designation

Engine 642

BE05.10-N-1001-03S

Wear dimension of timing chain stretch

independent of mileage

mm

 82

dependent on mileage

< 250,000 km

mm

-

> 250,000 km

mm

-

 Timing chain drive, toothed belt drive

Number

Designation

Engine 642 in model 639
Engine 642 in model 906

BA05.10-N-1006-01G

Measuring chain tensioner to cylinder head

Nm

20