7 Task Description
7.1 Engine
7.1.1 Engine – Barring manually
Preconditions
☑ Engine is stopped and starting disabled.
Special tools, Material, Spare parts
Designation / Use Part No. Qty.
Ratchet F30006212 1
Socket F30005655 1
DANGER
Unguarded rotating and moving engine components.
Risk of serious injury – danger to life!
• before barring or starting the engine, ensure that nobody is in the danger zone.
• After working on the engine, check that all protective devices have been reinstalled and all tools
removed from the engine.
Engine – Barring manually
1. Remove cover plate (2).
2. Attach ratchet with socket to barring tool.
3. Rotate crankshaft in engine direction of ro‐
tation. Apart from the normal compression
resistance, there should be no abnormal re‐
sistance.
Result: If the resistance exceeds compression re‐
sistance, contact Service.
4. For barring-tool removal follow reverse se‐
quence of working steps. TIM-ID: 0000002525 - 003
76 | Task Description | MW15407/14E 2012-02
7.1.2 Engine cranking on starter
Special tools, Material, Spare parts
Designation / Use Part No. Qty.
Connector pliers 0135315483 1
DANGER
Unguarded rotating and moving engine components.
Risk of serious injury – danger to life!
• before barring or starting the engine, ensure that nobody is in the danger zone.
• After working on the engine, check that all protective devices have been reinstalled and all tools
removed from the engine.
Engine cranking on starter
1. Disengage the bayonet union nut (4) of
connector X4 with connector pliers (2) and
withdraw connector (3) from Engine Control
Unit.
2. Bar engine in unloaded condition: Press
START button.
3. Let the crankshaft rotate until oil pressure is
indicated.
4. Engine start is automatically interrupted
when max. admissible starting period has
expired. Re-start engine after approx. 20
seconds if necessary.
5. Plug connector X4 (3) and use connector
pliers (2) to secure the bayonet union
nut (4) by turning it clockwise until it latches
into place.
TIM-ID: 0000031172 - 005
MW15407/14E 2012-02 | Task Description | 77
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.
Rigid endoscope Y20097353 1
Preparatory steps
1. Remove cylinder head cover (→ Page 89).
2. Remove injector (→ Page 95).
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.
Endoscopic examination of cylinder liner
Findings Action
• Thin carbon coating on circumference of carbon scraper ring No action required
• Slight localized additive deposits at top edge
• Localized smooth areas on bottom edge
• Carbon deposits on circumference in clearance 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
• Consistent honing pattern without objections
• First signs of marks left by lower cooling bores
• Running pattern seems darker
• Dark areas with even or varying degrees of discoloration Further endoscopic examina‐
• Beginning and end of the discoloration are not sharply defined and tion required as part of main‐
do not cover the entire stroke area tenance work
• Dark areas in the upper section of the cooling bore, remaining cir‐
cumference without objections
• Piston rings without objections
• On the entire circumference, apart from light areas of discoloration Cylinder liner must be re‐
(that do not impair operation) clearly darker stripes that start at the placed; Service must be con‐
TIM-ID: 0000000015 - 013
top piston ring tacted
• Heat discoloration in the direction of stroke and honing pattern dam‐
age
• Heat discoloration of piston rings
1. Compile endoscopy report using the table.
2. Use technical terms for description of the liner surface (→ Page 81).
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.
78 | Task Description | MW15407/14E 2012-02
Final steps
1. Install injector (→ Page 95).
2. Install cylinder head cover (→ Page 89).
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7.2.2 Cylinder liner – Instructions and comments on endoscopic and visual
examination
Terms used for endoscopic examination
Use the terms listed below to describe the condition of the cylinder-liner surface in the endoscopic exami‐
nation report.
Findings Measure
Minor dirt scores Minor dirt scores can occur during the assembly of a new engine (honing prod‐
ucts, particles, broken-off burrs). Removed cylinders clearly show such scoring
on the running surface under endoscope magnification. Cannot be felt with the
fingernail.
Findings not critical.
Single scores Clearly visible scores caused by hard particles. They usually start in the TDC
area and cross through the hone pattern in the direction of stroke.
Findings not critical.
Scored area These areas consist of scores of different length and depth next to one anoth‐
er. In most cases, they are found at the 6-o'clock and 12-o'clock positions (in‐
let/exhaust) along the transverse engine axis.
Findings not critical.
Smoothened area Smoothened areas are on the running surface but almost the whole honing
pattern is still visible. Smoothened areas appear brighter and more brilliant
than the surrounding running surface.
Findings not critical.
Bright area Bright areas are on the running surface and show local removal of the honing
pattern. Grooves from honing process are not visible any more.
Discoloration This is caused by oxidation (surface discoloration through oil or fuel) and tem‐
perature differences around the liner. It appears rather darker within the honed
structure in contrast to the bright metallic running surface. The honing pattern
is undisturbed. Discolorations extend in stroke direction and may be interrupt‐
ed.
Findings not critical.
Corrosion fields / spots Corrosion fields / spots result from water (condensed water) with the valves in
the overlap (open) position. They are clearly visible due to the dark color of the
honing groove bottom.
This corrosion is not critical unless there is corrosion pitting.
Black lines Black lines are a step towards heat discoloration. They are visible as a clear
discoloration from TDC to BDC in the running surface and the start of localized
damage to the honing pattern.
TIM-ID: 0000000014 - 013
Cylinder liners with a large number of black lines around the running surface
have limited service life and should be replaced.
80 | Task Description | MW15407/14E 2012-02
Findings Measure
Burn mark This is caused by a malfunction in the liner / ring tribosystem. Usually they run
over the whole ring-travel area (TDC/BDC), starting at the first TDC-ring and
becoming more visible from the second TDC-ring 2 onwards and less pro‐
nounced from TDC-ring 1. The honing pattern is usually no longer visible and
displays a clearly defined (straight) edge to the undisturbed surface. The dam‐
aged surface is usually discolored. The circumferential length varies.
Liners with burn marks, or heat discoloration, starting in TDC ring 1 have to be
replaced.
Seizure marks, scuff‐ Irregular circumference lengths and depths. Can be caused either by the pis‐
ing ton skirt or the piston crown. Material deposits on the liner (smear), heavy dis‐
coloration. Severe, visible scoring.
Replace liner.
Evaluation of findings and further measures
The findings in the start phase of oxidation discoloration and heat discoloration are similar. A thorough
investigation and compliance with the above evaluation criteria allow an unambiguous evaluation. To
avoid unnecessary disassembly work, it is recommended that another inspection be carried out after fur‐
ther operation of the engine.
TIM-ID: 0000000014 - 013
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7.3 Crankcase Breather
7.3.1 Crankcase breather – Cleaning oil separator element
Preconditions
☑ Engine is stopped and starting disabled.
Special tools, Material, Spare parts
Designation / Use Part No. Qty.
Fuel
Gasket (→ Spare Parts Catalog)
WARNING
Fuels are combustible.
Risk of fire and explosion!
• Avoid open flames, electrical sparks and ignition sources.
• Do not smoke.
WARNING
Compressed air
Risk of injury!
• Do not direct compressed-air jet at persons.
• Wear protective goggles / safety mask and ear protectors.
Crankcase breather – Cleaning oil
separator element
1. Remove cover (1) from housing (4).
2. Remove oil separator (2) and gasket (3).
3. Clean oil separator (2) in fuel and blow dry
with compressed air.
4. Moisten oil separator (2) with engine oil.
5. Place oil separator (2) with new gasket (3)
onto housing (4) and install cover (1).
6. Clean further oil separator element in the
same way.
TIM-ID: 0000003470 - 006
82 | Task Description | MW15407/14E 2012-02
7.3.2 Crankcase breather – Oil separator replacement, diaphragm check and
replacement
Preconditions
☑ Engine is stopped and starting disabled.
Special tools, Material, Spare parts
Designation / Use Part No. Qty.
Torque wrench, 6-50 Nm F30027336 1
Ratchet adapter F30027340 1
Filter element (→ Spare Parts Catalog)
Diaphragm (→ Spare Parts Catalog)
O-ring (→ Spare Parts Catalog)
WARNING
Hot oil.
Oil can contain combustion residues which are harmful to health.
Risk of injury and poisoning!
• Wear protective clothing, gloves, and goggles / safety mask.
• Avoid contact with skin.
• Do not inhale oil vapor.
Replacing filter element of oil
separator
1. Remove cover (2) with O-ring (3).
2. Remove filter element (1) from housing (4).
3. Insert new filter element into housing (4)
ensuring correct installation position, and fit
cover (2) with new O-ring.
4. Tighten screws of cover (2) to specified tightening torque.
TIM-ID: 0000003491 - 004
Name Size Type Lubricant Value/Standard
Screw Tightening torque 6 Nm + 2 Nm
5. Replace filter elements of further oil separators in the same way.
MW15407/14E 2012-02 | Task Description | 83
