Part 2: Engine Winterisation

Chapter 2: Engine Winterisation - The Core Task

The engine is arguably the most critical and vulnerable component during winter. Proper winterisation prevents freezing and corrosion within the cooling system and lubrication system.

2.1. Fuel System Treatment:

• Fill the Tank: Top off the fuel tank(s) to 95% full to minimise condensation and prevent diesel bug growth (for diesel engines).

• Add Fuel Stabiliser: Follow product instructions for appropriate dosage. Run the engine for 10-15 minutes after adding to ensure the stabilised fuel circulates throughout the system.

• Change Fuel Filters: If due, or after adding stabiliser, consider changing fuel filters to start fresh in spring.

2.2. Cooling System (Freshwater Cooled Engines):

• Drain Seawater System: Disconnect the raw water intake hose and drain any raw water strainers.

• Flush with Freshwater: Briefly run the engine on fresh water (using a bucket or flushing attachment) to clear salt and debris.

• Introduce Antifreeze: With the engine still running (or briefly running), introduce non-toxic marine antifreeze into the raw water intake until it exits the exhaust. This displaces all water and protects against freezing and corrosion. Follow engine manufacturer's instructions for quantity.

• Check Freshwater Coolant: Ensure the engine's internal freshwater cooling system (with engine-specific coolant) is at the correct level and has the proper freeze protection.

2.3. Cooling System (Raw Water Cooled Engines):

• Flush & Antifreeze: Similar to freshwater cooled, but the antifreeze directly circulates through the entire engine block. Ensure full displacement of saltwater.

2.4. Lubrication System:

• Change Engine Oil & Filter: It's best practice to change the oil before winter storage. Old oil contains contaminants (acids, moisture) that can corrode internal engine parts over time. Run the engine briefly after changing to circulate fresh oil.

• Change Transmission Fluid: If applicable, check and change transmission fluid according to manufacturer recommendations.

2.5. External Engine Protection:

• Fogging: Spray fogging oil into the air intake (carburetor/throttle body) while the engine is running and stalling to protect cylinder walls and pistons from corrosion.

• Belts & Hoses: Inspect for cracks, wear, or looseness. Replace if necessary.

• Remove Impeller: Consider removing the raw water pump impeller to prevent it from taking a permanent "set" during storage. Lubricate the pump housing.

• Clean Strainers: Clean any raw water strainers.

• Protect Air Filter: Cover the air intake with a rag or plastic bag to prevent pests from entering.