Cat C18 ACERT Marine Propulsion

Common issues

• Injector wear and fouling, leading to poor combustion, increased fuel consumption, and exhaust smoke.
• Turbocharger fouling (carbon buildup) or bearing wear, resulting in reduced boost pressure and engine power.
• Heat exchanger fouling (raw water side) or corrosion, causing elevated engine coolant temperatures.
• Sensor faults (e.g., oil pressure, coolant temperature, boost pressure, exhaust gas temperature) leading to inaccurate readings and potential derating.
• Coolant leaks from hoses, clamps, or heat exchanger end caps, compromising cooling system integrity.
• Fuel system contamination (water, particulates) leading to premature filter clogging and injector issues.
• Exhaust manifold cracks or gasket leaks, causing heat loss, reduced turbo efficiency, and potential fire hazard.
• Excessive engine vibration due to misfiring, worn mounts, or propeller imbalance.

Inspection checklist

• Visually inspect for any fluid leaks (oil, fuel, coolant) around the engine, hoses, and connections.
• Check engine oil level and condition (color, presence of water/fuel).
• Inspect fuel filters (primary and secondary) for signs of water or excessive particulate accumulation.
• Examine the turbocharger for excessive axial and radial shaft play, unusual noises, and signs of oil leakage.
• Check all drive belts (alternator, raw water pump) for proper tension and condition (cracks, fraying).
• Inspect the raw water pump impeller for wear or damage (if accessible without major disassembly).
• Verify proper operation of all engine alarms and safety shutdowns (e.g., low oil pressure, high coolant temperature, overspeed).
• Monitor engine parameters (oil pressure, coolant temperature, exhaust gas temperature, boost pressure, fuel pressure) during operation for deviations from normal.
• Inspect exhaust system for leaks, cracks, and integrity of thermal lagging.
• Check engine mounts for signs of deterioration, cracking, or excessive movement.

Service intervals

Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.

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 filters (primary and secondary)
• Engine oil filters
• Raw water pump impeller and gasket kit
• Drive belts (alternator, raw water pump)
• Common O-rings and gaskets (e.g., fuel line seals, heat exchanger end cap gaskets)
• Spare engine sensor (e.g., coolant temperature, oil pressure)
• Air filter element
• Emergency stop button/switch

Safety

• High-pressure fuel lines: Risk of fuel spray injury if lines are compromised while engine is running or pressurized.
• Hot surfaces: Exhaust manifold, turbocharger, and other engine components operate at high temperatures, posing burn hazards.
• Rotating machinery: Belts, pulleys, and flywheel present entanglement hazards when engine is running.
• Electrical hazards: Live electrical components and wiring can cause shock if not properly isolated during inspection/maintenance.
• Exhaust gases: Carbon monoxide and other toxic gases require proper ventilation in the engine room.

Class survey

A class surveyor will typically focus on: verification of engine logbook entries and maintenance records; operational testing of emergency stops and overspeed protection; functionality of engine alarms and safety devices; integrity of fuel lines (including double-walled where required) and shut-off valves; condition of exhaust system lagging and absence of leaks; security of engine foundation bolts; general cleanliness of the engine room and absence of oil/fuel accumulation; proper operation of the governor and load response; and overall engine performance during a sea trial or dockside load test to ensure compliance with regulatory and classification society requirements.

Estimated lifetime: 15,000 - 25,000 hours before major overhaul (for well-maintained commercial applications, pleasure craft may see less due to lower annual hours but similar age-related issues)