Engine Flush is an internal car engine cleaner. Suitable for both gasoline and diesel engines. Instructions for use: Check that the oil level in the engine is up to standard. Open the cap and pour the contents of the bottle into the engine through the oil cap. Let the engine idle for 10-20 minutes. Driving the car is prohibited while using Engine Flush! Drain the used oil from a warm engine. Change the oil filter and pour new oil into the engine. You will achieve the best results if you use Engine Flush during every oil change. Contains petroleum compounds.