Fleet managers today are trying to get every mile possible out of an oil change. Thanks to advances in additive technology in the past few years, many heavy-duty engine oils on the market do a great job helping fleet managers extend intervals. Unfortunately, great product marketing may have led many to believe that oil technology alone dictates drain intervals. Think again. Oil is only part of the solution. Several other factors need to be considered as well.

As the pressure to save money on labor and supplies while increasing fleet uptime has increased in recent years, many fleet managers may actually be overextending their drain intervals. This is dangerous territory. Overestimating the appropriate or optimized drain interval for the fleet could not only cause widespread engine failures, it could also quickly nullify any cost savings or profit margins resulting from the cost-cutting. To avoid this, one must move away from a mindset of "oil drain extension" to one of "oil drain optimization."

Oil drain optimization is not easy, but it's worth the time and effort invested in it. Fleet managers who put forth the time and effort to determine appropriate drain intervals are the ones who consistently meet their maintenance budget savings goals and see greater profit potential. To accomplish this, consider the following steps:

  1. Reference the engine and/or vehicle manufacturer's guidelines for oil intervals. It may sound basic, but manufacturer guidelines are often overlooked. While you will most likely choose to exceed the drain interval set by the manufacturer, its recommendation will help you to establish a baseline for optimal vehicle performance. For vehicles under warranty, however, exceeding the manufacturer's guidelines may be problematic. In these cases, it's best to consult the manufacturer directly to make sure that exceeding the manufacturer's guidelines does not void the warranty.

  2. Know the drain interval recommended by the oil filter manufacturer. Are you using a product that is built for the drain interval at which you're currently operating? If not, consider switching to an oil filter designed for longer service intervals.

  3. Evaluate the fleet profile. Ask yourself a number of investigating questions to best determine the stress placed on the fleet. Obviously, the more severe service the fleet regularly faces (for example, excessively hot or cold operating temperatures, loads, city driving pattern), the shorter the drain interval should be. Ask yourself the following:

      • What are my expectations from the fleet?

      • What improvements do I hope to achieve by pushing the drain interval?

      • What kind of load, weather and road conditions are the vehicles operating under?

      • What is the standard engine idle time? Long engine idle times may accelerate the rate of oil contamination and thus shorten oil drain intervals.

      • What is our average fuel economy? How much could we improve it?

  4. Consider how long you intend to keep the vehicles in your fleet. If the goal is to keep your current vehicles for 10 years or longer, pushing the drain intervals may not be in your best interest.
  5. Forecast the cost savings associated with longer oil drain intervals. Be sure to consider necessary investments in upgraded supplies, shortened engine rebuild frequencies etc. Seeing the cost/savings ratio will help you determine if extending the drain interval is a worthwhile venture.
  6. Communicate any maintenance changes to the drivers. Once you determine the optimal drain interval for your fleet, it's important to communicate that interval to the drivers and logistics manager. This will ensure the vehicle comes in for maintenance as scheduled.

In some rare cases, finding an optimal drain interval is not clear after walking through the steps above. In such instances, it's beneficial to call a meeting with the representatives from the engine, oil and filter manufacturers. When meeting with this group, outline the reasons for pursuing an optimal drain interval program and the desired goals. Together, they should be able to determine if those goals are realistic, and develop a program that includes the most appropriate products for your needs and circumstances.

The Oil Analysis Link
Whenever working with drain intervals that exceed the engine manufacturer's recommendation, strongly consider implementing an oil analysis program. Though oil analysis is often rejected because of the perceived cost, it is a cornerstone of any great fleet preventive maintenance program. It provides valuable information about the condition of the equipment, the condition of the oil and the presence of contaminants in the oil. There are ways to make such a program fit into your budget such as using oil analysis to determine the optimum oil drain frequency, then reducing the routine sampling frequency and possibly some of the testing performed. But in doing so, realize that some potentially important information will not be generated. In fact, many oil manufacturers will include oil analysis in their proposals.

If these steps seem excessive, they aren't. Considering the fact that most fleets on the road today have engines less than 10 years old, overextending drain intervals not only puts you at risk of unit failure, but you may also have to deal with extensive paperwork and questions if the engine is still under warranty. The engine manufacturer may ask for the service records and oil analysis history which is used to determine if the problem was due to a faulty engine or lack of proper maintenance. This may seem an extreme case, but it does happen occasionally.

Oil analysis can also be beneficial in improving the resale value of the power unit. Look at it this way: If you're buying a used truck, would you rather purchase the vehicle that comes with an oil analysis history showing excellent engine wear trends and system maintenance, or one that has no history available?

Above all, oil analysis acts as a report card for the fleet. It allows one to spot problems, often before they arise, therefore ensuring maximum service life for equipment. For example, issues with air induction, the cooling system and the fueling system may all be detected. The overarching value of oil analysis, however, is to ensure that the drain interval is indeed where it needs to be.

Optimized drain intervals can be achieved if you take the time to honestly evaluate the current maintenance program, set goals, draw on the expertise of suppliers, and make full use of regular maintenance and oil analysis. Most importantly, because federal regulations and your fiscal responsibilities change regularly, plan to reevaluate your preventive maintenance program every year. At that time, verify any actual cost savings or fleet uptime increases you enjoyed the previous 12 months, consider any maintenance issues you faced and make the necessary adjustments to the program.

Though there is no magic formula for achieving the ideal fleet maintenance program, especially where drain intervals are concerned, taking many of the steps described above may help you get the most out of your budget and ensure your fleet is as productive as it can be.