Currently, development of recycling, renewable, and sustainable products to replace fossil fuel products
is an essential matter for industrial profiteering as well as environment protection. In the present study,
waste cooking oil blended with SAE10W-40 should reduce the wear and friction on the piston skirt. Wear
and friction performance were evaluated using piston skirt-liner contact tester, and the piston material
was aluminum 6061. The design of experiment (DOE) was constructed using the response surface
methodology (RSM) technique. Influence of different operating parameters such as rotational speeds
(200 RPM, 250 RPM, 300 RPM), volume concentration (5% and 10% of waste oil), and loads (2 kg, 5.5 kg,
and 9 kg) were optimized. Based on the results of moisture content and viscosity; as the concentration
of waste cooking oil increases, the viscosity of the lubricant decreases. The lowest moisture content
was at the 5% volume concentration. The increase in the coefficient of friction occurred in 5% and 10% volume
concentration of waste cooking oil for both pairs. The RSM model showed that the speed, load, and
volume composition have a significant effect on the coefficient of friction (COF) and specific wear rate
(WR). The optimum obtained for both output (COF and WR) were 0.0596l for COF and 0.6827l for
WR. The relevant parameters such as speed, load, and volume composition are 200 rev/min, 9.0 kg and
0.7071% of volume concentration respectively. Afield emission scanning electron microscope (FESEM)
analysis shows mild abrasion, pitting corrosion, and severe delamination of the specimen surface
increased when running at higher load.