The Motul Engine Flush is a concentrated additive designed to clean the internal lubrication system of both gasoline and diesel engines—naturally aspirated or turbocharged, with or without emission after-treatment systems. Simply added to warm oil before an oil change, it circulates for about 10–15 minutes to dissolve sludge, varnish, and micro-deposits. While in operation, it continues to lubricate moving parts, helping prevent wear and overheating before the contaminants are removed during the oil drain.

Many users and engine-care professionals report that this cleaning treatment can restore smoother operation, enhance compression, improve fuel economy, and reduce harmful emissions, especially in engines with moderate buildup . However, there’s a cautionary side: particularly in high-mileage engines, aggressive flushing may dislodge deposits that can clog oil passages or strain seals, leading to potential issues. For older or heavily sludged engines, a gentler cleaning strategy—such as shorter oil intervals with quality oil or mild additives—is often preferred over using an engine flush every time.