To change the engine oil of a Piaggio Ape, start by lifting the vehicle with a jack and ensuring it is stable. This operation should be performed with the engine warm to facilitate oil drainage, so start the engine for a few minutes to warm it up, then turn it off before proceeding. Move the vehicle to a flat surface and place a container to collect the used oil under the drain plug. The plug is usually located at the bottom of the engine. Using a wrench, unscrew the plug and allow the oil to drain completely. If the oil filter is accessible, remove it with the appropriate tool, making sure to dispose of it properly. Once the old oil has fully drained, screw the drain plug back in. Then, proceed to fill with new oil, using a funnel to avoid spills. It is important to pour slowly to avoid overloading the engine. Check the oil level using the dipstick to ensure it is at the correct level, adding oil if necessary. After finishing, start the engine for a few minutes, turn it off, and recheck the level, adjusting it if needed. Finally, dispose of the used oil properly and check for leaks. The oil change should be performed periodically to keep the engine in good working condition.