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1 December 2014

As part of a progressive maintenance program and if done properly, extending oil change intervals can provide significant savings for a company operating heavy duty equipment.  Castrol’s field engineering team has a great deal of experience in helping customers to safely extend drain intervals.

The key word in that previous sentence is “safely.” Anyone can extend oil drain intervals, but to do it safely, so no increased wear or other damage occurs as a result, is another matter entirely.

Perhaps it is best if we first discuss why oil needs to be changed in the first place. You may have heard comments such as “oil doesn’t wear out, it just gets dirty” or “if you keep the oil clean you never have to change it.” Well, that simply isn’t true.

Yes, particulate contamination of lubricating oil is one of the major reasons why the oil must be periodically changed, but it’s not the only reason. Some of the other reasons why oil must be changed are depletion of additives, aging of the oil (oxidation/nitration) and accumulation of acids and corrosive compounds. With good filtration you can help achieve maximum service life of the oil by removing solid contaminants, but you still need to be concerned about these other issues.

When the oil becomes oxidized, the additives are depleted, or corrosive compounds start to build up in the oil, the only recourse you have is to drain the oil out and replace it with new fluid. In addition to filtration, other things that will help to achieve maximum service life for lubricants include preventing soot accumulation, overheating, and liquid contamination (i.e. water, diesel fuel, antifreeze, etc.). As we like to say, keep the oil clean, cool and dry.

Extending oil drain intervals is just one part of a progressive maintenance program, and it shouldn’t be the first part. Begin with an honest assessment of current maintenance practices. Creating a baseline is critical, as it will provide something to compare against after you’ve made changes to your maintenance practices. Once the assessment is completed, it is best to address any shortcomings observed in your maintenance practices first before starting to extend drains.

One key area that is a must for any oil drain extension program is the use of oil analysis. If you want to enjoy the economic benefits of extending oil change intervals, be prepared to improve your used oil analysis program first. Castrol’s field engineering team can help you do this, as it is made up of experts in the field of used oil analysis. Each member of the team is certified by the Society of Tribologists and Lubrication Engineers (STLE) as an Oil Monitoring Analyst and each member has many years of valuable industry experience.

Another area to consider is the actual lubricant being used or being considered for use.  Not all lubricants are created equal and not all lubricants are good candidates for an extended drain program. It is prudent to work with a lubrication specialist who can advise you on the suitability of lubricants in specific applications.

And finally, any process needs to be carried out in a stepped manner. Drain intervals should be increased incrementally over a period of time, and results should be measured in between steps.

This process cannot be rushed, as data must be gathered and examined and it must support stepping the interval out further. If you don’t have the data to support it, don’t do it. And, keep in mind that even with a well-designed and executed oil drain extension program, not every vehicle in your fleet will be a good candidate for extended drains.  There are always some bad actors that have issues such as high soot, fuel dilution, or coolant contamination, or other issues that make extending drain intervals impractical for that particular machine.

This is an important enough topic to warrant further discussion, so there will be additional articles in future editions of HD Focus. In the meantime, if you are interested in learning more about extending drain intervals, please contact your Castrol sales representative or field engineer for more information.