Common Problems We See With Marine Engines What lifespan would you give the marine diesel engine that’s powering your boat right now? 30 years? 20 years? Two? The answer depends on three factors

What lifespan would you give the marine diesel engine that’s powering your boat right now? 30 years? 20 years? Two? The answer depends on three factors:

  • How well you’ve stuck to your maintenance schedule
  • How you’ve run your engine and for how many hours per year
  • Who’s been servicing your vessel

Marine diesel engines are meant to last at least 10 to 30 years but can cop a serious dent in life expectancy if not managed well. Reliable and knowledgeable mechanics like THT can spot many issues from the moment they set eyes on them. Here are just a few.

Water Leaks

Ignoring leaks in either the closed-loop coolant circuit or the sea water circuit, will result in marine diesel engines overheating and premature failure.

THT’s solution: Replace leaking o-rings and rubber pipes as they start to become brittle or cracked. Clear away calcium deposits and conduct regular coolant flushes.

Contaminated Fuel in your Marine Engine

You’ll kick yourself if you end up with a premature fuel system overhaul when a simple clear bowl at the base of your primary filter can show you when a drain is needed. Contamination can come from fuel bug, algae growing in the tank or water from condensation, while newer ‘common rail’ fuel injectors have a lower tolerance for imperfections.

THT’s solution: Regular fuel filter changes and constant monitoring of fuel condition is essential.

Is Your Marine Diesel Engine Mounted Correctly?

An incorrectly fitted engine may initially sit well but over time, vibration can work an incorrect fitting loose or shear bolts and break engine mounts. The engine and gearbox must be aligned within a 1000th of a millimetre to the propeller shaft. That’s pretty much a perfect fit. Anything less and big issues will result.

THT’s solution: Use a knowledgeable, expert team of marine mechanics to get it right and help avoid expensive rebuilds.

Slipping Drive Belts

Such a simple item to check and maintain but still drive belt maintenance is overlooked.

They operate many things, from the closed circuit coolant pump to additional components like a deck wash pump. Belts that become worn, perished or loose can cause multiple system failures. To check their validity, with engines off, push every belt at its centre point. It should have anywhere between 0.5cm and 1.5cm give. Too tight and they can break. Too lose and they’ll slip.

THT’s solution: Check and replace your drive belts regularly. Always have a spare set of EVERY belt on board.

Loose Electrics

Avoid the ‘green death’ – the corrosion of copper wires. First, any loose plugs and connections should be secured so that no wires are exposed. Second, make sure your bilge is dry. Salt water in the bilge equates to salt in the air and that’s disaster for copper.

THT’s solution: A dry bilge and secure electrics keeps your marine diesel engine salt-free and happy.

How THT Sales Can Help Avoid These Common Problems

The simple design of marine diesel engines means they can last well beyond the minimum 10 – 30 year life expectancy but only with regular maintenance. If you’re looking for some maintenance tips, or would rather leave the whole job to the experts, the team at THT are ready to complete all service and repairs to get you ship-shape and on the water. Call us today to book in your next service.