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ENGINEERING SOLUTIONS / Post date: 1 January 2016

This article continues our focus on the cost-saving opportunities that can result from safely extending drain intervals. Please note that you can find earlier articles in this series by checking out the Related Articles links at the bottom of this webpage.

Extending drain intervals is really all about reducing costs and increasing operational efficiency. So, what are the benefits? Well, there can be both hard savings that can be relatively easily determined and soft savings that may be less tangible and harder to quantify.

First let’s look at the hard savings. Extending drain intervals should:

  1. Reduce consumption of lubricants
  2. Reduce labor costs


Like all consumables, lubricants have a per-unit price. When drain intervals are extended, less oil needs to be purchased, which results in less expenditures and less labor as a result of fewer oil changes. Determining these cost savings is simple, as numbers just need to be plugged into a formula.

As an example, let’s say that by increasing the drain interval on a diesel engine from 250 hours to 300 hours you can reduce the number of oil changes per year from 8 to 6.6 (on a machine that incurs 2,000 hours of use per year), which saves 1.4 oil changes per year. On a machine with a 10-gallon oil sump capacity that means an annual reduction in oil consumption of 14 gallons per year. Now multiply that by the number of machines in the fleet… for a fleet with 24 units, for example, that is a reduction in oil consumption of 336 gallons of oil. Now multiply that by the cost of the oil… if the oil is priced at $8.00 per gallon, then the cost saved by this simple drain extension equals $2,688.00 per year.

This doesn’t include the savings on labor. If your maintenance people spend 30 minutes on an oil change, you‘ve reduced your labor usage by 16.8 hours. Multiply that by your labor cost rate… with an internal labor rate of $45.00, you’ve just reduced your costs by another $756.00. This will also free up your maintenance people to complete other more pressing tasks, which is a benefit knowing that many companies are operating with reduced staffs.

There are some soft savings that need to be considered as well. With reduced oil consumption you won’t need to purchase as much oil, so fewer orders need to be placed with your lubricant supplier and fewer purchase orders need to be created and closed. You will receive fewer deliveries, which will reduce the time spent dealing with the deliveries, as well as your exposure to oil spills during the tank-filling process.

Also, with fewer oil changes being performed, you will reduce your exposure to environmental contamination by reducing the chances of having an oil spill occur during the process of draining and handling used oil. You will also reduce your exposure to worker injuries that can occur during the oil change process. And you’ll reduce the amount of waste oil you have to handle and store on the premises until it can be disposed of properly. These liabilities are less tangible than the hard savings discussed above, but they are very real.

Now, keep in mind that the above example is all based on a very modest increase of only 50 hours to the drain interval. Castrol’s HD Field Engineering team has worked with many customers to safely extend their drain intervals much further through a strenuous program that often includes an upgrade in lubricant quality, an enhanced used oil analysis program, and training on proper fluid handling and contamination control.

The process of extending oil drain intervals typically includes starting conservatively and working slowly to extend drains as maintenance practices are improved across the company and data is gathered and compiled into management reports that allow evaluation of the drain extension program. When done correctly, oil drain intervals can be extended safely, which can bring considerable savings to a business. Often times, through the process of improving maintenance practices, the overall health of the fleet improves dramatically, which can increase the life of equipment, improve its resale value, and further reduce costs for the business.

As mentioned in the beginning of this article, please review the previous articles we’ve posted for additional information on safely extending your drain intervals.

As always, Castrol’s HD Field Engineering team is available to help design an oil drain extension program for your business. Please contact your Castrol sales representative for assistance.