7.3 Cylinder Liner
7.3.1 Cylinder liner – Endoscopic examination
Preconditions
☑
Engine is stopped and starting disabled
Special tools, Material, Spare parts
Designation / Use
Part No.
Qty.
Rigid endoscope
Y20097353
1
Preparatory steps
1.
Remove cylinder head cover (→ Page 158).
2.
Positioning crankshaft at BDC
1.
Using barring gear, turn crankshaft until crankshaft journal of the cylinder to be inspected has reached BDC.
2.
Insert endoscope into cylinder liner through injector seat.
Cylinder liner – Endoscopic examination
Findings
Task
• Thin carbon coating around circumference of carbon scraper ring
• Slight localized additive deposits at top edge
• Localized smooth areas at bottom edge
• Carbon deposits around circumference between top piston ring and
bottom edge of carbon scraper ring
• First signs of marks left by top piston ring
• Bright mark around circumference
• Faultless, even honing pattern
• First signs of marks left by lower cooling bores
• Running pattern seems darker
No action required.
• Darker areas of even or varying color intensity
• Beginning and end of the discoloration are not sharply defined and do
not cover the entire stroke area
• Dark areas in the upper section of the cooling bore, remaining circum-
ference cannot be faulted
• Piston rings faultless
Further endoscopic examina-
tion required as part of mainte-
nance work.
• On the entire circumference not only bright discoloration (not critical
for operation) clearly visible darker stripes that begin at the top piston
ring
• Heat discoloration in the direction of stroke and honing pattern dam-
age
• Heat discoloration of piston rings
Cylinder liner must be replaced,
contact Service.
1.
Compile endoscopy report using the table.
2.
Use technical terms for description of the liner surface (→ Page 150).
3.
Depending on findings:
• Do not take any action or
• Carry out further endoscopic examination as part of maintenance work or
• Contact Service; cylinder liner must be replaced.
148 | Cylinder Liner | MS150031/06E 2016-010
TIM-ID: 0000000015 - 016
