Cylinder Liner; Cylinder Liner - Endoscopic Examination - MTU 12 V 4000 M33F Operating Instructions Manual

6.2 Cylinder Liner

6.2.1 Cylinder liner – Endoscopic examination
Preconditions
☑Engine is stopped and starting disabled
Special tools, Material, Spare parts
Designation / Use
Rigid endoscope
Preparatory steps
1. Remove cylinder head cover (→ Page 178).
2. Remove injector (→ Page 182).
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
• 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
• 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 cir-
cumference cannot be faulted
• Piston rings faultless
• On the entire circumference not only bright discoloration (not criti-
cal for operation) clearly visible darker stripes that begin at the top
piston ring
• Heat discoloration in the direction of stroke and honing pattern
damage
• Heat discoloration of piston rings
1. Compile endoscopy report using the table.
2. Use technical terms for description of the liner surface (→ Page 169).
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.
MS150069/02E 2014-03 | Task Description | 167
Part No. Qty.
Y20097353
Task
No action required.
Further endoscopic examina-
tion required as part of mainte-
nance work.
Cylinder liner must be replaced,
contact Service.
1