AMSOIL UPPER CYLINDER LUBRICANT: Preserves Horsepower; Performance New as of October 2019: AMSOIL Upper Cylinder Lubricant (UCL) is the latest addition to the gasoline additive lineup. It delivers more lubricity than the competition and battles ethanol-related corrosion. Upper cylinders are one of the toughest areas of an engine to lubricate due to the intense heat […]