Valve medic, an additive for hydraulic valve lifters. 354ml. Oil additive. Cleaner for oil channels and conditioner for hydraulic valve lifters. It allows you to achieve the double result: clean the oil system before regular oil change and eliminate noises from hydraulic valve lifters during engine start and operation. The product make engine operation more even, improves oil flow to the hydraulic supports. Application: Warm up and stop the engine. Pour it into the crankcase (following the proportion for 5 - 6 liters of oil) and start the engine. Knocking may return in case of late oil change or a damage of the crankcase ventilation system which requires mechanical repair.