For many of us, there’s nothing more pleasurable than sitting at anchor in a secluded cove in southeast Alaska, or on the northern British Columbia coast. Many of us do just that every year, cruising for two to five months at a time. But what if you are new to diesel motors and/or extended cruising. How do you go about preparing your diesel for cruising to ensure your boat’s power-plant is ready for the challenge?

Preparing Your Diesel for Cruising

Problems will arise, but you can prevent many of the common setbacks with pre-trip preventive maintenance.


  • Complete all scheduled maintenance
  • Inspect the engine and transmission
  • Identify distributor, dealers, and authorized service centers
  • Collect serial numbers
  • Spare parts & tools

Failures are inevitable, and it’s all about how you hand the issues that will contribute to the quality of your cruise.

Readying Your Diesel

First, make sure you’ve completed all the scheduled maintenance recommended by the engine and transmission manufacturers. This includes looking under the hood, something we all have gotten out of practice doing since diesels have become so reliable. An engine-room inspection only takes a few minutes and could prevent an expensive breakdown.

Obviously, engine oil level is crucial, a diesel engine won’t run very long without it, but don’t obsess over keeping the oil exactly at the full mark. Too much oil can mean it is being diluted by diesel fuel, and cloudiness or milkiness indicates water contamination; either case requires immediate attention. Tip:Engine oil shouldn’t smell like fuel, nor should it feel gritty, and it’s normal for diesel engines to turn their oil black.

When working properly, clear plastic reservoirs on most boats provide a visual reference of engine coolant level, but an improperly functioning heat exchanger cap or pinhole in the hose that connects the reservoir to the heat exchanger may prevent fluid from siphoning from the reservoir. Tip: If the reservoir is low when the engine is cold and near full when the engine is hot, it’s likely working properly.

Inspect the engine for oil, fuel, seawater or coolant leaks. A mirror and flashlight can help your search. Black soot around the manifold, turbos or exhaust risers indicate exhaust leaks, which are particularly damaging as the abrasive soot clogs air filters and wears cylinder linings. Inspect fuel filters bowls with a flashlight, looking for a telltale light-coffee-colored layer of sludge in the bottom that indicates water in the fuel or the heavy sediment that suggests clogged filters; also check seawater strainers for debris.

Recommend servicing seawater pumps annually, and clean and test cooling system every two or three years. Belts, hoses, clamps and motor mounts must be inspected. Valve adjustments vary by the engine manufacturer.

Second, take your operator’s manual into your engine room, find a comfortable place to sit and identify all the main components while reviewing maintenance and service topics. Doing so will not only assist you in understanding exactly where things are but also identify any special parts and/or tools you’ll need to deal with them.

Third, find the names of engine distributors, dealers and authorized service centers along your route. Also, make sure you have a service and parts manual along with a serial number of your engine and transmission; many technicians can help you if they have this information. Purchase the correct spares, enough engine lube oil and filters required during your cruise, power steering fluid and transmission oil and filters, primary and secondary fuel filters, and a couple of gallons of antifreeze.

Also, extra drive belts, air-cleaner element, raw-water pump impeller, gaskets and seals for sea strainers, replacement zincs for the heat exchanger, a selection of hose clamps and tie-wraps, and spare fuses and relays.

And don’t forget the correct tools. If your plans include remote locations, you’ll want to carry and extra alternator, a complete sea-water pump, a set of spare injectors, and a complete gasket set. Most engine distributors have “cruise kits” available with many of the items above.

Once all the prep work is complete, the spares and tools properly stowed, and nothing is sitting loose that could be thrown around the engine room during rough water conditions, you’re ready to give the command to cast-off.



Now, all that’s left to do is kick back and enjoy one of those secluded coves with peace of mind!

Visit our online bookstore and download a copy of Preparing Your Diesel for Cruising ebook.