Operating instructions

7.2 Cylinder Liner
7.2.1 Cylinder liner – Endoscopic examination
Preconditions
☑ Engine is stopped and starting disabled
Special tools, Material, Spare parts
Designation / Use Part No. Qty.
Endoscope
Y20097353
Preparatory steps
1. Remove cylinder head cover (→ Page 76).
2. Remove injector (→ Page 79).
Positioning crankshaft at BDC
1. Using barring device, turn crankshaft until crankshaft journal of the cylinder to be tested has reached
BDC.
2. Insert endoscope into cylinder liner through injector seat.
Cylinder liner endoscopic examination
Findings Measure
• Thin carbon coating on carbon scraper ring
• Slight localized additive deposits at top edge
• Localized smooth areas at bottom edge
• Carbon deposits on entire circumference between top piston ring
and bottom edge of carbon scraper ring
• First signs of marks left by top piston ring
• Bright mark on entire circumference
• Faultless, even honing pattern
• First signs of marks left by lower cooling bores
• Running pattern seems darker
No action required
• Dark areas with even or varying degrees of discoloration
• 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 cir‐
cumference cannot be faulted
• Piston rings cannot be faulted
Further endoscopic examina‐
tion required as part of main‐
tenance work
• On the entire circumference, apart from light areas of discoloration
(do not impair operation) clearly darker stripes that start 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 re‐
placed; Service must be con‐
tacted
1. Compile endoscopy report using the table.
2. Use technical terms for description of the liner surface (→ Page 61).
3. Depending on findings:
• Do not take any action or
• carry out a further endoscopic examination as part of maintenance work or
• contact Service; cylinder liner must be replaced.
M015675/05E 2011-10 | Task Description | 59
TIM-ID: 0000003304 - 003