Lowash, or low ash oil, is a type of motor oil specifically formulated for use in modern cars that feature engines with catalytic converters. As the name suggests, it contains a lower amount of ash compared to regular engine oils. Ash is produced when certain additives are burned in the combustion chamber; these include detergents and dispersants which help to keep your engine clean and running smoothly. Lowash reduces the amount of ash generated by these substances so as not to damage delicate parts such as oxygen sensors and catalytic converters which can be affected by high levels of ash accumulation. It also helps reduce emissions from your vehicle since less unburned fuel escapes into the environment through exhaust gases. Lowash should only be used in vehicles where specified by either the manufacturer or an authorized service center; otherwise you risk damaging both your engine and its components due to inadequate lubrication.