Inspect cylinders with a light probe

AR01.00-P-0200LFB

Inspect cylinders with a light probe

08.08.2019

Engine

157, 256.9, 276, 277, 278, 279 in model 222

Engine

157, 276, 278, 279 in model 217

Modification notes

05.08.2019

Reference document AH05.30-P-1000-02SZ added.

Operation step 8.

1

Endoscope

Shown on model 222 with M256

51

Screw

53

Screw

52

Coolant vent line

54

Coolant thermostat connecting pipe

 Caution

Risk of injury caused by scraping or cutting body parts on sharp vehicle parts

Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.

AS00.00-Z-0017-01A

 Warning

Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.

Wear protective gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

 

Remove/install

1

Unfasten the clamps for the charge air lines on the water-cooled charge-air cooler, unclip the water-cooled charge-air cooler from the lower retaining clamp and pull forward with the coolant lines still connected.

Engine 276.8 in model 217, 222

AR09.41-P-6819LFA

2

Switch off ignition and store transmitter key outside of transmitter range (min. 2 m).

3

Remove the spark plug on the cylinder to be checked.



Engine 157, 276, 278 in model 222
Engine 157, 278 in model 217

AP15.10-P-1580HA



Engine 277, 279 in model 222
Engine 279 in model 217

AP15.10-P-1580AAA



Engine 276.8 in model 217

AP15.10-P-1580D



Engine 256.9 in model 222

AP15.10-P-1580E

4

Unscrew the bolt (51) for the coolant bleed line (52) at the fan unit.

Engine 256.9 in model 222

5

Unscrew the bolt (53) from the coolant thermostat connecting pipe (54) on the cylinder head.

Engine 256.9 in model 222

 Screw, coolant connecting pipe to cylinder head

*BA20.20-P-1002-02MRT

6.1

Rotate the engine at the crankshaft center bolt in the direction of engine rotation until the piston of the cylinder to be checked is at bottom dead centre.

Engine 157, 276, 277, 278, 279 in model 222
Engine 157, 276, 278, 279 in model 217

 Socket wrench bit

*001589650900

6.2

Rotate the engine at the crankshaft vibration damper in the direction of engine rotation until the piston of the cylinder to be checked is at bottom dead centre.

Engine 256.9 in model 222

 Counterholder

*654589004000

7

Connect the endoscope (1) and guide the endoscope lens through the spark plug threaded bore into the cylinder to be checked.



000 588 01 21 00 Endoscope

WS01.00-P-0097B



Check

8

Check the cylinder barrels, piston crowns and valves.

General information on checking valves, valve seats and valve guides

AH05.30-P-1000-02SZ

General information on inspecting cylinder walls

Engine 278 in model 217, 222

AH01.00-P-0300-01MM

General information on inspecting cylinder walls

Engine 276.9 in model 222

AH01.00-P-0300-01A

General information on inspecting cylinder walls

Engine 157, 277, 279 in model 222
Engine 157, 279 in model 217

AH01.00-P-0300-01VA

General information on inspecting cylinder walls

Engine 256.9, 276.8 in model 222
Engine 276.8 in model 217

AH01.00-P-0300-01AMG

If the condition of the cylinder barrels is not clearly recognizable,



Remove cylinder head.

Left cylinder head
Engine 157, 278 in model 217
Engine 157, 278 in model 222

AR01.30-P-5770LFB

Right cylinder head
Engine 157, 278 in model 217
Engine 157, 278 in model 222

AR01.30-P-5780LFB

Left cylinder head
Engine 276.9 in model 222

AR01.30-P-5770LFH

Right cylinder head
Engine 276.9 in model 222

AR01.30-P-5780LFH

Left cylinder head
Engine 276.8 in model 217, 222

AR01.30-P-5770LFA

Right cylinder head
Engine 276.8 in model 217, 222

AR01.30-P-5780LFA

Left cylinder head
Engine 277, 279 in model 222
Engine 279 in model 217

AR01.30-P-5770MUB

Right cylinder head
Engine 277, 279 in model 222
Engine 279 in model 217

AR01.30-P-5780MUB

Cylinder head
Engine 256.9 in model 222

AR01.30-P-5800MRT

9

Install in the reverse order.

 Engine radiator, coolant hoses and lines

Number

Designation

Engine 256

BA20.20-P-1002-02MRT

Screw, coolant connecting pipe to cylinder head

Nm

8