DC-17

Common issues

• Fuel injector fouling or wear, leading to poor combustion, increased exhaust temperatures, and reduced efficiency.
• Piston ring wear and cylinder liner scuffing, resulting in increased lube oil consumption, blow-by, and potential loss of compression.
• Bearing wear (main, connecting rod, camshaft) due to lubrication oil degradation, contamination, or insufficient flow, causing abnormal noise and potential seizure.
• Turbocharger bearing failure or impeller damage (due to foreign object ingestion or lube oil issues), leading to reduced engine power, excessive smoke, and whistling noises.
• Cooling system blockages (e.g., seawater strainer, heat exchanger fouling, freshwater scale buildup) causing engine overheating and potential thermal stress.
• Fuel system contamination (water, microbial growth, particulates) leading to filter clogging, fuel pump damage, and erratic engine operation.
• Corrosion of external components, piping, and structural elements due to prolonged exposure to marine atmosphere and saltwater spray.
• Electrical and control system malfunctions (sensors, wiring harnesses, control unit) caused by vibration, moisture ingress, or component aging.

Inspection checklist

• **Visual Inspection**: Check for any oil, fuel, or coolant leaks. Inspect for signs of corrosion on the engine block, piping, and mounting points. Verify condition of belts, hoses, and wiring harnesses. Observe exhaust gas color (should be clear to light haze).
• **Fluid Levels & Condition**: Verify lube oil and cooling water levels. Check lube oil condition (color, smell, presence of water/fuel). Inspect fuel filters for excessive contamination or water accumulation.
• **Operational Check**: Start the engine and observe starting characteristics. Monitor critical parameters (lube oil pressure, cooling water temperature, exhaust gas temperatures per cylinder, RPM, load) at idle and under load. Listen for abnormal noises or vibrations.
• **Safety Devices**: Verify the functionality of the overspeed trip, low lube oil pressure shutdown, and high cooling water temperature shutdown. Check last test dates.
• **Fuel System Integrity**: Inspect high-pressure fuel lines for leaks, proper shielding, and secure fastening. Check fuel pump and injector external condition.
• **Air Intake & Exhaust System**: Inspect air filters for cleanliness. Check turbocharger for excessive axial/radial play (if accessible and safe). Inspect exhaust manifold and piping for cracks, leaks, and insulation integrity.
• **Engine Mounts & Foundation**: Inspect engine mounting bolts for tightness and signs of corrosion. Check engine foundation for cracks or structural fatigue.
• **Electrical System**: Inspect control panel, gauges, and alarm indicators for proper functionality. Check wiring for chafing, loose connections, or signs of overheating.

Service intervals

Typical wear limits

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

Critical spares

• Full set of fuel filter elements (primary and secondary).
• Full set of lube oil filter elements.
• Air filter elements.
• Fuel injector nozzle tips or complete injectors.
• Gasket set for cylinder head and common access covers.
• Assorted O-rings and seals for fuel, lube oil, and cooling water systems.
• Drive belts (for cooling pump, alternator).
• Fuses and common electrical relays/sensors (e.g., lube oil pressure, cooling water temperature).

Safety

• **Rotating Machinery**: Ensure all guards for rotating parts (flywheel, belts, shafts) are securely in place to prevent entanglement.
• **Hot Surfaces**: Exhaust manifold, turbocharger, and engine block reach high temperatures. Verify insulation is intact to prevent burns and reduce fire risk.
• **High-Pressure Fuel**: Leaks in high-pressure fuel lines can create a fine, ignitable spray (diesel mist). Ensure proper shielding and double-wall piping where required.
• **Exhaust Gases**: Ensure exhaust system integrity and adequate ventilation to prevent accumulation of toxic gases (CO, NOx) in machinery spaces.
• **Electrical Hazards**: Always follow lockout/tagout procedures before working on electrical components. Be aware of live circuits during troubleshooting.
• **Overspeed**: Verify the functionality and calibration of the overspeed protection system to prevent catastrophic engine failure.

Class survey

During annual class surveys, the surveyor will typically check the engine's operational performance, verify the functionality of all safety devices (overspeed, low oil pressure, high temperature shutdowns), and inspect the general condition of the engine, its auxiliaries, and associated piping (fuel, lube oil, cooling, exhaust). Documentation review (logbook, maintenance records, oil analysis reports, previous survey reports) is crucial. Special attention is paid to fuel system integrity (leakage, shielding), exhaust system condition (insulation, leaks), and the security of engine mounts and foundation. The DNV TA certificate TAM0000088 will be verified for validity.