You can change your marine diesel engine oil yourself by following these instructions.

Use only a Marine Diesel Engine Oil of good quality.

  • 5 liter and 10 liter drums are easy to use and can be refilled with old oil for correct disposal.
  • Change your oil and filter at least every 100 hours. Keep spare oil filters on board at ALL times.

Many old marine engines use a lot of oil and will require plenty of spare oil for long passages.

  • For good engines—Straight 30 W.
  • For worn engines—Straight 50 W.

Always keep plenty of rags, degreaser and oil-absorbent materials on board your boat. This is a messy job. Always clean engine and bilge after oil/fuel filter changes.

Always run a marine engine for about 10 minutes before oil change to heat oil or you will not be able to pump it out, even with a good quality oil sump pump.

Some Fuel Injection Pumps have sumps with engine oil (e.g. Lucas & Sims); this must be changed at the same time as diesel leaks back and dilutes fuel and reduces viscosity—oil level then goes up. This can happen to engine sump on some marine engines with internal return lines.

Removing Filters: Cut open 2 liter milk container, hold beneath filter, remove filter and drop into container, then place this container into a bucket with rag in the bottom. This system will save you some time in cleaning.

Use the same method for fuel filters.

Fitting filters: Smear oil on rubber seal before fitting. Do not fit too tightly

  • If possible, fill filter with oil before fitting.
  • Check filter is not leaking and oil level is correct after a momentary run.

Many thanks to Laurence Burgin for this brief outline of changing your marine diesel engine oil. A full description is included in Laurence’s e-book Marine Diesel Engine Basics now available for download from Amazon.

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