The practice of blending used motor oil into diesel fuel has been around for many years.
The main advantage is the oil never leaves your direct control, so you don’t have to worry about cleanup liability due to improper handling by a third party.
Rollins Leasing Corp.® currently blends used oil with diesel at some 90 to 95 of its 196 shops. According to James Wright, VP-Maintenance, blending has worked well for them. There have been no problems either with engines or with the blending process itself.
The fleet uses a variety of portable units that filter and store approximately 35 gallons of drained oil. When the shop gets a fuel delivery, the units automatically mix in oil at a predetermined percentage and that’s the end of Rollins’ oil disposal cycle.
While there’s no realistic way to completely eliminate used oil from your fleet waste stream, as long as you’re examining all your disposal options you might also want to look at ways to reduce that stream.
For example, just by extending the drain interval from 25,000 to 30,000 miles, Rollins has cut its used oil volume from 500,000 to 300,000 gallons a year without any increase in engine work, according to Ralph Grant. The company wins in two ways: buying less new oil and having less oil to cart off.
There are many ways to go about extending oil drains, ranging from oil analysis programs to after-market engine filter systems. Choosing one depends largely on your specific operation, equipment, disposal costs, and willingness to experiment with proven maintenance practices.
Condensed from June 1995 Fleet Owner magazine article Used Oil: Gone But Not Forgotten.