S90ME-C10.5

Common issues

• Hydraulic Power Unit (HPU) malfunctions (pressure drops, pump wear, filter clogging) affecting fuel injection and valve actuation.
• Fuel Injector Nozzle Clogging/Wear, particularly with HFO/VLSFO, leading to poor combustion, high exhaust temperatures, and potential liner damage.
• Exhaust Valve Spindle Burning/Sticking due to high temperatures, poor fuel quality, or hydraulic actuator issues.
• Cylinder Liner Scuffing/Excessive Wear caused by poor lubrication, cold corrosion (with high sulfur fuels), or poor combustion.
• Crosshead Bearing Wear due to high loads and potential lubrication breakdown, especially critical for long-stroke engines.
• Turbocharger Bearing/Rotor Imbalance or fouling, leading to reduced efficiency, high exhaust temperatures, and potential damage.
• Control System Sensor/Actuator Failures, given the electronic nature, can lead to engine derating or shutdown.
• Scavenge Space Fires/Fouling from accumulation of unburnt fuel and lube oil residues.

Inspection checklist

• Verify HPU operating pressures, check for leaks, and note filter change history and condition.
• Conduct visual inspection of cylinder units via scavenge ports for liner surface condition (scuffing, wear), piston ring condition, and scavenge port cleanliness.
• Check exhaust valve actuation for proper operation, listen for blow-by, and observe exhaust gas temperatures for deviations.
• Inspect fuel injection system integrity, including high-pressure pipes for leaks, nozzle cooling, and exhaust gas color.
• Perform crankcase inspection: check Oil Mist Detector (OMD) readings, listen for unusual bearing noises, and visually inspect for oil sludge.
• Inspect turbocharger: check bearing play (axial/radial), look for blade damage (compressor/turbine), and listen for unusual noises.
• Review Engine Control System (ECS) alarms (active/historical) and critical sensor readings (temperatures, pressures, speeds).
• Inspect engine foundation bolts and chocking for tightness, signs of movement, or corrosion.
• Verify proper operation of fuel oil supply and treatment system (purifiers, heaters, viscosity control) for HFO/VLSFO.
• Check cooling water system integrity for leaks, proper temperatures, and review chemical treatment records.

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Complete Fuel Injector Unit (at least one per cylinder type)
• Exhaust Valve Spindle & Seat Ring (at least one set)
• Piston Rings (full set for one cylinder)
• Cylinder Liner (at least one, due to long lead time)
• Crosshead Bearing Shells (top and bottom halves)
• Turbocharger Bearing Cartridge or Repair Kit
• HPU Hydraulic Pump/Motor Spares (e.g., seals, bearings, or complete spare pump)
• Critical Control System Sensors/Actuators (e.g., speed sensors, pressure transducers, HCU components)

Safety

• Crankcase Explosion Risk: Ensure Oil Mist Detector (OMD) is functional and alarms are tested. Adhere to crankcase entry procedures.
• High-Pressure Fuel Oil Leaks: Atomized spray can cause fire or severe injection injury. Inspect all high-pressure lines and safety shielding regularly.
• Hot Surfaces & Exhaust Gas System: Risk of severe burns. Ensure insulation is intact and warning signs are present.
• Moving Machinery & Entanglement: Crankshaft, connecting rods, crossheads, turbocharger rotor. Ensure guards are in place and strict Lock-Out/Tag-Out (LOTO) procedures are followed during maintenance.
• High-Pressure Hydraulic System: Risk of fluid injection injury. Ensure proper PPE and depressurization procedures are followed before any work.

Class survey

For ME-C engines, Class Surveyors will focus on the reliability of the electronic control system and hydraulic power unit (HPU) in addition to traditional mechanical checks. During Special Surveys (5-year cycle), expect opening of a minimum of 25% of cylinder units (piston, liner, exhaust valve), main and crosshead bearings, crankshaft deflection measurement, and comprehensive inspection of the fuel injection system. Verification of all safety devices, alarm functions, emergency stops, and the functionality of the OMD is paramount. Specific attention will be paid to the integrity of the fuel changeover system and low sulfur fuel handling components.

Estimated lifetime: 150,000 - 250,000 running hours before requiring major, extensive overhaul (e.g., crankshaft regrinding, full engine dismantling).