Ultimate engine protection. Original formula. New! E-z pour bottle. Since 1923. Add to gas & oil. Helps extend engine life. Improves motor oil performance. Cleans & lubricates entire fuel system. For best results add 4 ounces to each 10 gallons of gasoline or diesel fuel. For fleet use in bulk tanks add 1 quart (32 oz) to each 100 gallons of gasoline or diesel fuel. Marvel Mystery Oil combats internal motor rust and corrosion, lubricates valves, piston rings and upper cylinder walls, and eliminates valve sticking. Keeps rings free and reduces piston and cylinder wear. It also keeps fuel pump and carburetor parts clean, eliminating need for frequent adjustments. Marvel Mystery Oil retards formation of power-dissipating motor deposits, such as gum, varnish and sludge. Added to Diesel Fuel: Marvel Mystery Oil increases fuel mileage. Cleans and keeps fuel pumps, injectors, and nozzles free from harmful fuel residues. Reduces upper cylinder wear. Promotes longer piston ring life and assures less frequent overhauls. Retards souring of fuel and lubricates the entire fuel system. This diesel fuel additive does not comply with federal ultra-low sulfur content requirements for use in model year 2007 and newer diesel motor vehicles or model year 2011 and newer diesel nonroad equipment engines. Added to Crankcase Oils: One quart of Marvel Mystery Oil added to crankcase oils (do not fill above oil level) will prevent gum, sludge, varnish and harmful residues; will neutralize acid formations and improve viscosity index, protect hydraulic valve lifters, and will reduce harmful effects due to crankcase oil dilution. In new or rebuilt motors, Marvel Mystery Oil gives protection against scouring or seizing. Produces highly polished wear-resistant finish on engine surfaces, which helps maintain newness of motors. Winter-Proofing Other Lubricants: 4 to 8 ounces of Marvel Mystery Oil per quart of oil (depending upon viscosity and climate) makes winter starting quick and easy, protects against damage resulting from cold, stiff lubricants and eliminates motor oil's tendency to congeal. Made in USA.