Marine Diesel Maintenance Schedules

Diesel Engine Maintenance

The modern, lightweight diesels that are now being installed in sailboats are marvels of reliability. They will provide many thousands of hours of trouble-free service, but only if basic engine maintenance is done.

The following checklists cover periodic maintenance. Tasks are grouped into recommended engine-hour intervals. If you don't use your engine very much, you should still perform the 500-hour check annually and the 1000-hour check every other year.

Click here for a list of recommended spare parts and supplies for diesel engines. This section also includes links to outside resources for further reading on diesel maintenance.

Fuel System

The most important thing to do for your diesel engine is to keep the fuel clean. Every effort should be made to buy clean fuel and keep it clean. Nothing will kill a diesel engine faster than dirty fuel. Bacterial growth in your fuel tank is a direct result of water in the fuel tank. The most common source of water in your fuel tank is a fuel filler cap that isn't sealing properly. It is possible, although rare, to get a bad batch of diesel fuel that is contaminiated with water. Some cruisers in more remote locations will use a "baja" style filter to remove water as they fill their diesel tanks. An internal or external fuel polishing system can be used to clean fuel already in your tank and remove water.

Cooling System

The most important task of your engine coolant isn't cooling, it's prevention of corrosion. The anti-corrosion properties of coolant wear out well before its cooling properties wear out. For this reason, it's important to replace the cooling solution every two years (at least).

Diesel Engine - Each Use Checklist

Perform the following checks each time you use your engine:

	Task	Link to Detail
Alarm System
	Check the operation of warning lights and gauges by turning the key and watching the instrument panel to see if the lights come on.
Cooling System
	Check coolant level in "burp bottle"
	Inspect cooling system for any leaks
	Check for cooling water flow after the engine has been started
	In weed prone areas, check raw-water strainer on a daily basis
Electrical System
	Check voltmeter while the engine is running to see if alternator is charging the batteries.
Fuel System
	Inspect fuel filter bowl / water separator for dirt or water
	Run your hands over the fuel lines, filters, and pump feeling for any evidence of leaking fuel . There should be no diesel fuel smell at all near the engine.
	With the engine running, note the reading on the fuel vacuum gauge (if installed) . Clean filters should read about 2-8 inches of vacuum.
General Inspection
	Look for signs of wear on belts and hoses
	Look for any fluids leaked into the drip pan underneath the engine
	Look for any wires that may have vibrated loose, especially around the alternator and starter. WARNING: there are energized wires at these two locations that carry high amp loads. Do not wear finger rings or watches with metal bands when performing this inspection. A short circuit can result in a serious burn.
	Check your exhaust at start-up for excess smoke. Large amounts of white or blue-white smoke can indicate coolant in the cylinders (possbile head-gasket problem), and black smoke can indicate a problem with unburned diesel fuel (dirty injectors or similar).
Lubrication
	Check engine oil level each time before you start the engine
	Inspect engine sump for evidence of leaking oil
Transmission
	Look for evidence of leaking fluids

Diesel Engine 100 Hour Checklist

Perform the checks from the list above, plus the following:

	Task	Link to Detail
Cooling System
	Check raw water strainer; remove any debris
	Check coolant level in engine by attempting to top off with 50/50 mix of coolant and water. Perform this on a cold engine only .
	Check the siphon-break valve for buildup of salt.
	Check cooling water through-hull intakes for barnacles or other growth.
Electrical System
	Check alternator belt tension; look for evidence of wear
	Check for any loose wires or chafing of wiring harness
Fuel System
	Drain water/sludge from fuel filter bowl.
	Inspect primary fuel filter and replace if needed
Lubrication
	Change engine oil and filter
Misc.
	Check throttle and shift linkages for any signs of wear or misalignment. If lubrication is needed, don't use an oil that will attract dirt (e.g. WE40) - use a dry lubricant (silicone spray, graphite, etc.)
Transmission / Drive Train
	Check transmission fluid level, according to manufacturer's procedure. Top off if necessary, being careful not to overfill.
	Inspect stuffing box. Drip rate should be 1-3 drops per minute when sitting at anchor.

Diesel Engine 500 Hour (or annual) Maintenance List

Perform the checks from the lists above, plus the following:

	Task	Link to Detail
Alarm System
	Check the operation of warning lights and gauges.
Cooling System
	Change pencil zincs in engine cooling system (if installed)
	Check all hoses carefully. Check hose clamps to see if they're still tight and are not corroded. Make sure hoses are not kinked or collapsed where they make sharp turns. All hoses should be double-clamped.
Electrical System
	Remove alternator belt and check alternator bearings for wear. Replace with new alternator belt. Note, heavily loaded belts may not last 500 hours. Check yours on a regular basis.
	Test engine sensor warning lights and buzzer
Engine Mechanical
	Retorque head bolts to manufacturer's spec
	Set valve clearances
	Check engine mounts for signs of compression or wear. Check nuts to make sure they're tight.
Exhaust System
	Check exhaust hose for signs of wear
Fuel System
	Inspect fuel filter bowl / water separator
	Inspect deck fill cover, especially the o-ring. This is a common source of water in your diesel fuel.
Misc.
	Wire-brush any external rust, prime and paint
Transmission / Drive Train
	Inspect stuffing box for drip rate; replace shaft packing if necessary.
	Inspect shift linkages and controls for loose or corroded parts
	Check shaft coupling bolts; retorque if necessary

Diesel Engine 1000 Hour (or every two years) Maintenance List

Perform the checks from the lists above, plus the following:

	Task	Link to Detail
Cooling System
	Remove heat exchanger core and clean
	Inspect oil cooler (if one is installed on your engine)
	Change coolant following manufacturers instructions
	Change raw water impeller; save old impeller for a spare
Engine Mechanical
	Perform compression test on all cylinders
	Have fuel injectors cleaned and calibrated
Exhaust System
	Remove exhaust elbow and check for build up of carbon or other deposits that would cause restrictions.
Transmission / Drive Train
	Check alignment of propshaft and transmission. Adjust engine mounts as needed.

Links to Outside Resources

The following links provide links to further reading, manufacturers websites and more information on "how to"

	Item	Link
Diesel Maintenance Tips
	Good discussion of diesel maintenance and why diesels require more maintenance than gasoline engines from D.H. Pascoe & Co., Marine Surveyors.	Link
	Fuel system maintenance tips from BOAT/US	Link
	Reader forums from BoatDiesel.com	Link
Hands-on Diesel Classes
	Mack Boring runs a very popular series of classes on diesel maintenance for cruising sailors.	Link

Manufacturers & Dealers
	Beta Marine / Phasor (Kubota)
	Mack Boring - parts distributor	Link
	Perkins
	Torresen Marine - parts distributor	Parts Forums
	Universal
	Volvo
	Westerbeke	FAQ's
	Yanmar

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