The oil system in the A5 is a dry sump forced lubrication system that ensures proper lubrication of dynamic engine components. Starting at the Rotax oil tank, oil travels to the oil thermostat and then to the oil cooler. From the oil cooler, the oil is sucked to the bottom of the engine by the oil pump. The oil is then filtered and sent throughout the engine. The oil return line sends the oil back from the bottom of the crankcase to the oil tank—specifically, against the oil tank wall in a swirling motion to prevent air from mixing with the oil. The oil dipstick is located beneath the oil tank cap. The purge hose at the top of the oil tank is used for ventilation and is routed in a continuous decline. The Curtis valve is used to drain the oil.