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Inspect Cylinders With A Light Probe - AR01.00-P-0200MFG

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Engine 139 in model 118, 177, 247 

G16054011Courtesy of MERCEDES-BENZ USA
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
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
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
Topical note  Notes on avoiding damage through contamination and foreign objects   AH00.00-P-5000-01A
REMOVINGINSTALLING Remove/install     
1 Remove spark plugs.    
REFER TO MAINTENANCE     AP15.10-P-1580J
    INSTALLATION IMPORTANT Only install upper Engine cover after the leak test.  
2 Remove front section of the front right fender liner.   AR88.10-P-1301MFA
INSPECT Check     
3 Turn Engine at belt pulley of crankshaft in direction of Engine rotation until piston of cylinder to be checked is at bottom dead center (BDC). NOTES Do not turn Engine opposite direction of Engine rotation.
Otherwise, the timing chain will jump and Engine damage will occur.
SPECIAL TOOL Counterholder
Fig 1
4 Connect endoscope (1) and insert flexible endoscope through spark plug thread bore into the cylinder to be checked.    
5 Check cylinder barrel, piston crown, and valves.   AH05.30-P-1000-02SZ
  General information on checking valves, valve seats and valve guides   AH01.00-P-0300-01AMG 
  General information on inspecting cylinder walls IMPORTANT If there is "scoring" (wear to the cylinder), the cylinder barrel has become rough and the honing marks are no longer visible.
If "scoring" (wear to the cylinder) is recognizable,

Remove cylinder head and check cylinder barrel again.
AR01.30-P-5800MFG 
6 Perform check of additional cylinders in same manner.    
7 Install in the reverse order.    
8 Carry out Engine test run and check Engine for proper leak tightness and leak tightness.    
9 Install upper Engine cover.    
REFER TO MAINTENANCE     AP01.10-P-2405-01K
Fig 1: Identifying Counterholder (654 589 00 40 00)
G11971953Courtesy of MERCEDES-BENZ USA