Piston crown damage
Seizure due to overheating (mainly piston crown)
- Overheating due to combustion defaults
- Bent/blocked oil injection jet
- Installation of incorrect pistons
- Malfunctions in the cooling system
- Clearance restriction in the upper sliding surface area
Impact marks
- Piston protrusion too great
- Excessive remachining of the cylinder head sealing surface
- Incorrect valve recess
- Incorrect cylinder head gasket
- Carbon deposits on the piston crown
- Insufficient valve clearance
- Incorrect valve timing caused by incorrect adjustment or a slipped toothed belt
Fused/melted off material
- Faulty injection nozzles
- Incorrect quantity of injected fuel
- Incorrect injection point
- Insufficient compression
- Ignition delay
- Oscillating injection lines
Cracks in the crown and crown bowl
- Faulty or incorrect injection nozzle
- Incorrect injection point
- Incorrect quantity of injected fuel
- Insufficient compression
- Lack of piston cooling
- Installation of pistons with incorrect bowl shape
- Improvement in performance (e.g. chip tuning)
Piston ring damage
Material washout in the ring area
- Incorrectly installed pistons
- Fuel flooding
- Severe axial wear of the ring groove and piston rings
- Ring flutter
Radial wear due to fuel flooding
- Fault during mixture formation
- Combustion defaults
- Insufficient compression pressure
- Incorrect piston protrusion dimension
Axial wear due to ingress of dirt
- Abrasive dirt particles due to inadequate filtration
- Dirt particles that are not completely removed during
reconditioning of the engine (chips, blasting agent) - Abraded particles caused when the engine is being run in
Piston skirt damage
Asymmetrical piston wear pattern
- Bent/twisted connecting rod
- Connecting rod eyes bored at an angle
- Cylinder bore not straight
- Individual cylinders not installed straight
- Excessive connecting rod bearing clearance
45° seizure
- Excessively narrow fit of the piston pin
- Seizure in connecting rod eye (inadequate lubrication at initial start-up)
- Incorrectly installed shrink-fit connecting rod
Dry running/Fuel damage
- Over-rich engine running
- Combustion defaults (misfiring)
- Insufficient compression
- Defective cold-start device
- Oil dilution with fuel
Cylinder liner damage
Cavitation
- Poor/inaccurate seating of the cylinder liner
- Use of incorrect O-ring seals
- Use of unsuitable coolant agent
- Insufficient prepressure in the cooling system
- Operating temperature too low/too high
- Restricted coolant flow
Bright spots in the upper cylinder area
Carbon deposits on the piston top land due to:
- Excessive ingress of oil into the combustion chamber due to defective components
- Increased emissions of blow-by gases with oil entering the intake air system
- Insufficient separation of oil vapour from the blow-by gases
- Frequent idling or short-distance drives