How do I change the engine oil on Freedom, and what should I check during the service?

Change Freedom's engine oil while warm, replace the oil filter and required seals, then run the engine and check for leaks and the correct oil level. Identify the engine model and filter arrangement first: the available Yanmar procedures cover both a cartridge filter with a cap tightened to 25 Nm and a screw-on filter with a different tightening method.

Identify the engine and parts

Read the model and serial number from the engine identification plate before buying oil or filters. Freedom's name alone cannot tell you which engine is fitted, its oil capacity or its service interval. If the engine has been replaced, the original boat handbook may be misleading.

Check the matching engine manual for oil viscosity, performance specification, refill quantity including the filter, and the service interval in hours or calendar time. Do not assume your usual diesel oil or a full five-litre container is correct.

• Obtain the correct Yanmar filter or a replacement explicitly cross-referenced to that engine.
• For the cartridge arrangement described here, obtain all three replacement stem O-rings.
• Have an oil extraction pump, waste container, funnel, absorbent pads, gloves and the appropriate socket or filter wrench ready.
• Use a torque wrench that can accurately apply 25 Nm if the engine has the cartridge cap covered by that procedure.

Warm and extract the oil

Record the engine hours and check the dipstick level before starting. A rising level, a strong diesel smell or milky oil needs investigation, not just an oil change. Black oil alone is normal in a working diesel.

With cooling water available, run the engine until the oil is warm enough to flow readily. Stop it, remove the starting key and prevent accidental starting before working near hot oil, belts or pulleys.

1. Place absorbent pads beneath the filter and protect the bilge from spills.
2. On the cartridge-filter arrangement, loosen the filter cap one or two turns and wait a few minutes for retained oil to drain into the crankcase.
3. Remove the dipstick and insert the extractor tube through its opening, following the pump instructions. Do not force a tube that catches.
4. Pump the oil into a suitable container and note roughly how much comes out. Investigate any large discrepancy from the expected quantity.

Replace the filter and refill

For the cartridge system, remove the cap and filter assembly, pull the old element from its stem and replace all three stem O-rings. Clean the seating surfaces. Lightly coat the new seals with clean engine oil and fit them in their original grooves without twisting them.