VISCOSITY TUTELA® Diesel Fuel System Cleaner is a multi-functional additive that helps keep your fuel system clean, improves combustion, provides for smoother engine operation, and can restore power loss and provide increase in fuel economy. Suitable for all the latest generation engines. Recommended to be used every 200 hours for maximum benefits. Method of Use: Application to individual unit or to a bulk fuel storage tank. Dosage: 32 oz (1 quart) treats up to 250 gallons of fuel. Storage: Unopened and stored at room temperature away from direct sunlight, for at least 3 years.