Yanmar 4JH series service intervals

The Yanmar 4JH series (4JH4, 4JH5, 4JH80, 4JH110) is a common inboard sailboat diesel. Oil and oil filter: every 250 hours or annually, use Yanmar-spec 15W40 API CF or CI-4 marine diesel oil. Fuel filter (primary and secondary): every 250 hours or annually. Air filter: inspect every 250 hours, replace as needed. Coolant: every 2 years, use Yanmar Long Life Coolant (green, ethylene glycol). Belts: inspect every 250 hours, replace at signs of cracking or glazing. Impeller: every 500 hours or 2 years, Yanmar recommends carrying a spare aboard. Zinc anodes (heat exchanger, oil cooler): inspect every 250 hours. Valve clearance: every 500 hours (intake 0.20mm, exhaust 0.40mm cold). Injectors: cleaning at 1000 hours, replacement per condition. First major service at 500 hours includes valve check and coolant test. The 4JH80 (electronic common rail) requires more careful fuel filtration than earlier mechanical variants.