PM Series: PM Task – Change Engine Oil & Analyze


Oil change recommendations vary greatly between engine manufacturers, models, applications, and can even vary depending upon the brand and rating of the oil used.  For example a John Deere 6068TFM75 used in a recreational marine application should have its oil changed every 250 hours or annually, whichever occurs first.  If you use John Deer Plus-50 oil or an oil meeting an E4-E7 ACEA rating, this interval can be extended 50% to 375 hour or annually.  Be sure to check your engine manufacturer to verify the correct maintenance schedule.

Courtesy of John Deere 6068 Owner’s Manual

Always remember that even if you have not met the hour requirement for an oil change within a given year, it is imperative that the oil still be changed at least annually.  There are several failure modes to oil as it ages.  When an engine runs cool,  moisture can build up through condensation within the engine.  This moisture combines with residual sulfur  from the diesel fuel.  This combination creates sulfuric acid which can damage sensitive engine components.  Additives and detergents which are designed to clean and neutralize contamination in the oil as well as to prevent corrosion and wear break down over time and must be replenished.  Also, extended oil changes can cause carbon created during combustion to overwhelm the remaining detergents, creating sludge.

Now if you find the opposite to be true and you are running several thousand hours per year, you may want to speak with your engine manufacturer or dealer about installing a centrifuge or bypass filtration system, such as an Alfa Laval or PuraDYN system, on your engine.  These systems add extra filtration, they may supply additives and detergents back to the oil, as well as some even have heaters to burn off any water and fuel that are trapped in the oil.

Oil Analysis

When reviewing engine manufacturer recommendations, you will also see that most manufacturers recommend oil analysis with every oil change, or at least annually.  Oil analysis is great for trending engine failures over time but it can also highlight issues of immediate concern such as a heat exchanger or injector failure as shown in the two sample reports shown below.

Those people doing extended oil changes require more frequent sampling and should also be using an advanced analysis including TBN or Total Base Number which measures the amount of active additives left within the oil.

When sampling oil, follow proper sampling procedure, see our website at

To purchase oil sampling supplies, check out our on-line store 

About our “Preventative Maintenance (PM) Series”

The PM Series addresses a PM found on most vessels by highlighting the requirements for a specific piece of equipment and then expand on equipment variations and techniques.  While you may not have the specific equipment referenced in the PM Series, the concepts should apply to your equipment.  The PM Series presents actual PMs taken from the WheelHouse Maintenance Management System.  WheelHouse users will always have the PMs and related documents and parts that are specific to their equipment.  Non WheelHouse users  should refer to their manufacturers guidance for your specific equipment when completing maintenance.  Contact WheelHouse for a product demonstration and pricing information.

Posted in Maintenance Log.