Dont put clean oil into a dirty engine. Nulon Engine Oil Flush is formulated to remove harmful contaminates from your engine while also creating a clean environment to keep your new oil free from sludge, dirt and carbon build-up for longer. It is also great for noisy hydraulic lifters that may be sticking due to contaminant build up. Nulon Engine Oil Flush is simple to use, just add 1 bottle for up to 6L of engine oil, start engine and idle for 10-15 minutes and drain while warm. Suitable for use with all petrol, diesel and LPG engines and is safe to mix with all oil types including mineral, semi-synthetic and full synthetic blends.