Don\'t add new oil to a dirty engine – flush it first. Engine flush effectively removes sludge and other unwanted deposits from the oilways before you add your fresh oil. New oil stays cleaner between changes. Essential for petrol and diesel engines . One 250ml Engine Flush bottle for each flush. All car and light van petrol and diesel engines. Add contents of bottle to oil in the engine – 250ml bottle will treat 4-6 litres of engine oil. Run engine for 15 to 20 minutes. Drain the oil, change the oil filter and refill with the recommended grade of Millers engine oil.