6L6EY18AL

Common issues

• Turbocharger bearing wear or fouling due to contaminated lube oil or carbon deposits, leading to reduced efficiency and smoke under load.
• Fuel injector nozzle clogging, erosion, or poor atomization, especially when operating on HFO, causing uneven combustion and high exhaust temperatures.
• Exhaust valve burning or seat wear, particularly with HFO operation, resulting in loss of compression and increased exhaust gas temperatures.
• Cylinder liner wear (ovalization/taper) leading to increased lube oil consumption and blow-by.
• Piston ring sticking or breakage, impairing sealing and heat transfer, and contributing to blow-by.
• Main and connecting rod bearing wear or damage, often due to lube oil contamination, insufficient pressure, or misalignment.
• Fuel pump element wear or malfunction, affecting fuel delivery timing and quantity.
• Cooling system blockages (e.g., seawater side fouling, freshwater side scaling) leading to overheating.

Inspection checklist

• Turbocharger: Check for axial and radial play of the rotor, signs of oil leakage from bearings, and fouling on compressor and turbine blades. Listen for unusual noises.
• Fuel System: Inspect all high-pressure fuel lines for leaks (especially critical with HFO), check fuel filter differential pressure, and monitor fuel pump rack positions for even load distribution.
• Lubrication System: Verify lube oil pressure and temperature, check for oil leaks, inspect oil filters, and perform crankcase inspection for blow-by or abnormal mist.
• Exhaust System: Inspect exhaust manifold and piping for leaks. Monitor individual cylinder exhaust gas temperatures for consistency, indicating balanced combustion.
• Cooling System: Verify freshwater and seawater pressures and temperatures. Inspect heat exchangers for signs of fouling or leaks, and check expansion tank levels.
• Cylinder Head Area: Listen for abnormal combustion noises (knocking, misfiring). Visually inspect for fuel or lube oil leaks around injectors and valve covers.
• Governor & Linkages: Check for smooth, responsive operation of the governor and its linkages, ensuring no excessive play or stiffness.
• Vibration & Noise: Conduct a general walk-around inspection, listening for unusual noises (e.g., knocking, grinding) and feeling for excessive vibrations from the engine block and auxiliaries.

Service intervals

Typical wear limits

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

Critical spares

• Fuel Injector Nozzles (or complete injectors)
• Fuel Filter Elements (all stages: primary, secondary, fine)
• Lube Oil Filter Elements
• Exhaust Valve Spindles and Seats (or complete exhaust valve assemblies)
• Piston Rings (at least one full set per cylinder)
• Main and Connecting Rod Bearing Shells (one set each)
• Various O-rings and Gaskets (especially for fuel, lube oil, and cooling systems)
• Turbocharger Bearing Cartridge (if serviceable onboard)

Safety

• High-Pressure Fuel Leaks: Risk of fire or explosion, particularly with HFO. Ensure all high-pressure fuel lines are properly shielded and regularly inspected for leaks.
• Hot Surfaces: Exhaust manifold, turbocharger, and engine block operate at high temperatures. Risk of severe burns. Ensure proper insulation and warning signs.
• Rotating Machinery: Exposed rotating components (flywheel, shaft couplings, turbocharger) pose entanglement hazards. Verify all guards are in place and secure.
• Crankcase Explosions: While rare with proper maintenance, accumulation of oil mist can lead to explosions. Monitor crankcase pressure and ensure ventilation systems are functional.
• Exhaust Gas Leaks: Risk of asphyxiation or carbon monoxide poisoning in enclosed engine room spaces. Regularly inspect exhaust system for integrity.

Class survey

For annual surveys, focus on operational tests of safety devices (overspeed, low LO pressure, high CW temp), visual inspection for leaks, general condition, and review of maintenance records. Intermediate surveys may require more detailed visual inspections and potentially opening selected cylinder heads for exhaust valve inspection, especially if HFO is used. Special Surveys (typically every 5 years) are comprehensive, requiring opening of main and connecting rod bearings for inspection/renewal, crankshaft deflection measurement, full cylinder head overhaul, piston and liner withdrawal for inspection/measurement, and turbocharger major overhaul. All safety devices, alarms, and documentation must be verified.

Estimated lifetime: 16,000 - 24,000 hours before first major overhaul; total design lifetime typically 80,000 - 120,000+ hours with proper maintenance and subsequent overhauls.