Main Engine 4-Stroke · Main Engines (4-Stroke)
The Volvo Penta D4/D6-MP is the commercial propulsion version of the D4 and D6 marine diesel engines, available in four- and six-cylinder form. It is a turbocharged diesel with electronic engine control, used to drive propellers through a marine gearbox on commercial vessels. Listed approvals are DNV class and IMO Tier II emission compliance.
What our service work and the manufacturer documentation say about keeping this model running.
Servicing per the manufacturer's manual and classification society requirements. Annual inspection at class survey. Stock spare parts as specified by the manufacturer.
| Engine oil and filter | 200-250 hours or annually, whichever comes first |
|---|---|
| Fuel filters (primary and secondary) | 200-250 hours or annually, whichever comes first |
| Air filter | 200-250 hours or annually (inspect/replace as needed) |
| Seawater pump impeller | 200-250 hours or annually (inspect/replace) |
| Valve clearance check/adjustment | 500-1000 hours |
| Coolant replacement | 2 years or 1000 hours |
| Heat exchanger cleaning (freshwater/seawater side) | 500-1000 hours or every 2 years |
| Turbocharger inspection | 500-1000 hours |
| Crankshaft deflection | Maximum deviation typically <0.10mm across webs |
|---|---|
| Cylinder liner wear | Max ovality/taper typically <0.15-0.20mm |
| Main/Connecting rod bearing clearances | Within manufacturer's specified limits (e.g., 0.08-0.15mm max) |
| Turbocharger shaft play | Axial play typically <0.15mm, radial play <0.50mm (check manufacturer's specific values) |
| Injector spray pattern | Visual assessment for even, fine atomization; no dribbling or streaking |
| Belt tension | Deflection within manufacturer's specified range (e.g., 10-15mm deflection under 10kg force) |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Class surveyors will typically check engine documentation (maintenance records, logbook, certificates), conduct an operational test under load (if possible) to verify performance and alarm functions (overspeed, low oil pressure, high temperature shutdowns). They will inspect the integrity of the fuel system (fire valves, piping, leak detection), exhaust system (insulation, leaks, support), engine mountings, cooling system, and emergency stop arrangements. General engine room cleanliness, ventilation, and fire-fighting provisions related to the engine are also assessed.
Estimated lifetime: 20,000 - 30,000 hours before major overhaul, with proper maintenance
Keep fuel filter and water separator elements, oil filters, drive belts, a seawater pump impeller and sets of gaskets and seals on board. Hold spare coolant hoses and common sensors for the engine control system.
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