Rusty Liner and Gear Teeth-1

Tips for looking after a dormant engine

Engine Maintenance


We were recently contacted by a vessel owner whose engines had not been started for 3 years.

Sensibly he had commissioned a borescope inspection, but it revealed internal corrosion within the engine and gearbox.

Rusty Liner and Gear Teeth-1

This would indicate that the engine and gearbox had not been correctly preserved before being taken out of service.

Here are our top tips for preserving an engine during extended dormant periods:

1 – 3 months of no use

  • Run the engine to normal operating temperature
  • All fluids remain in the engine
  • Seal all openings on the engine
  • Shut air flap valves

More than 3 months

  • Drain existing engine oil
  • Fill the sump with approved preserving oil to normal operating levels
  • Drain existing fuel and refill the fuel system with approved fuel (not standard diesel)
  • Fill the cooling system with an approved glycol-based antifreeze
  • Run the engine to normal operating temperature.
  • Spray corrosion inhibitor into the air inlet whilst barring the engine using the starter motor
  • Seal all openings
  • Spray external non-painted surfaces with corrosion inhibitor

If you need any further advice on this or assistance with your engines, let me know we’d be happy to help.

We’d recommend taking the time to ensure your engine is prepared for any major change – whether that’s dormancy, or a drastic change in temperature.

A few months back we shared some advice on what to do to prepare your engine for winter – if you missed it, you can click here and read it now.

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