How to Add Engine Oil to Diesel Fuel

Updated April 17, 2017

Burning used engine oil in diesel fuel is a way to save money on engine oil disposal costs. Few realise that used oil can be processed on-site as an alternative to traditional disposal methods. With the construction of a simple rope apparatus anyone can filter used oil. Every gallon of waste oil burnt in diesel results in savings approximate to the cost of a gallon of diesel fuel.

Collect used engine oil from every oil change. Pour the oil into 2-liter soda bottles using a funnel to avoid spillage.

Construct the used engine oil filtration apparatus. Place a 5-gallon bucket on the top and bottom of a shelf. Measure out enough rope to reach from the bottom of the bucket on the bottom shelf to the bottom of the bucket on top shelf. Cut the rope.

Pour used engine oil into the bucket on top of the shelf once a significant amount has been collected. Insert one end of the rope cut in Step 2 into the bottom bucket and insert the other end into the top bucket. Verify that the rope touches the bottom of both the top and bottom bucket. Cover the shelf with a transparent plastic tarp and place bricks on the tarp where it touches the ground. The bricks should prevent air from flowing underneath the tarp. If too much air contacts the oil during filtration it can contaminate the oil with dust, making it unusable.

Wait two to four weeks for the oil to filter through the rope due to capillary action. When the oil flows through the rope, contaminates are filtered out, making it suitable as a diesel fuel additive. Periodically check on the filtration progress by peering through the transparent tarp, but do not under any circumstances disturb it by introducing fresh air.

Pour the filtered oil in the bottom bucket into 2-liter soda bottles using a funnel.

Find out what ratio of engine oil to diesel is appropriate for your vehicle. While a one to 100 filtered oil to diesel ratio is typical, it may vary depending on various factors, such as weather conditions and model of the vehicle. Contact the vehicle's manufacturer for further advice.

Pour 1/2 gallon of filtered oil and 49 1/2 gallons of diesel into a 50-gallon drum. Cover the fuel mixture until its ready to use. Preferably an engine oil mixing device should be used if available.

Burn the fuel mixture in a diesel vehicle to dispose of the engine oil.

Store filtered engine oil for up to a year. After this time the oil begins to degrade, making it unusable as a diesel fuel additive.


Replace the rope used in the filtration apparatus every two to four batches of oil, depending on how much oil is filtered in each session. The contaminants in the oil impede oil flow through the rope, preventing filtration. Buy an oil mixing device if you plan on burning a large volume of filtered engine oil, as mixing in a 50-gallon drum can become impractical.


Although a rope can remove most of the contaminants from used engine oil, some may remain. For this reason only burn filtered oil in older model vehicles to offset the possibility of potential engine damage. Used engine oil is extremely toxic and has been shown to cause cancer. Wear protective clothing during handling and wash any exposed skin directly after handling.

Things You'll Need

  • Natural fibre rope
  • Shelf
  • 5-gallon buckets, 2
  • Transparent plastic tarp
  • Bricks
  • Funnel
  • 2-liter soda bottles
  • 50-gallon drum or oil blending device
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About the Author

Samuel Sohlden began his freelance writing career in 2007. His work appears on various websites, with articles focusing on science and health. In 2010 he attended the Intel International Science and Engineering Fair in San Jose, Calif. Sohlden is pursuing a Bachelor of Science in microbiology from the University of Cincinnati.