The STP® fuel additive products are individually labeled for proper dosage. This information can be found on the back label of the bottle. Typically, our products treat between 14-21 gallons. See similar questions...

Except for octane boosters, the ratio of fuel additives to fuel is not critical because the same quantity of detergent chemical passes through the fuel system and injectors/carburettors. Generally, the additives are formulated so that one bottle treats one tank of fuel. Please refer to the Product Information Sheets for the application of octane boosters. See similar questions...

The STP® fuel additive products are individually labeled for dose and treatment intervals. This information can be found on the back and neck labels of the bottle. See similar questions...

I have a Westerbeke/Universal engine/generator and need to know the correct amount of oil for my unit and the recommended oil change intervals. See similar questions...

Yes. All of the STP® products have been extensively tested and are safe for use in all cars. Always remember to follow the usage recommendations, which are clearly indicated on the label. See similar questions...

No. All STP® products undergo extensive testing to evaluate their performance and are determined to be safe for use in vehicles, both new and old. Our products are specifically formulated to help improve the performance of the gasoline or oil to which they are added and will, therefore, help maintain the performance of your car. See similar questions...

STP® products are completely compatible with all other standard fuel and lubricant additives that are intended for similar use. However, mixing fuel or lubricant additives is neither recommended nor should it be necessary. See similar questions...

STP® Complete Fuel System Cleaner is our most powerful fuel system cleaner. It not only does the job of our Super Concentrated products, but it also cleans the combustion chambers. The fuel system has a demanding job of delivering the proper fuel and air mixture to the engine, to give you the performance you need. See similar questions...

In order to obtain a good mixture of the product in the tank, Wynn’s recommends you pour fuel additives into the tank before topping up. However, it is not imperative, because vehicle movement will quickly mix the additive with the fuel. See similar questions...

Residuumsol: Fuel Oil Additive is a liquid blend of organic chemicals in a petroleum base. The ingredients of Residuumsol: Fuel Oil Additive include detergents, combustion catalyst, chemicals that reduce the surface tension of the fuel oil, oxidation inhibitor and deposit modifiers. Residuumsol: Fuel Oil Additive is easily miscible and fully compatible with all varieties of fuel oil. See similar questions...

The time proven remedy is to add a gallon of kerosene for each 10 to 20 gallons of fuel to the tank, then allow it to sit long enough for the kerosene to diffuse into the fuel. In weather below -20 degrees F, one gallon of kerosene for 10 gallons of fuel will keep things moving, but fuel economy will be reduced. Kerosene now has red dye which a DOT inspector will assume is off-road diesel. Be prepared for a hassle if you are checked. See similar questions...

These fuel additives are referred to as "Keep Clean" products. Just as brushing your teeth keeps harmful bacteria from building up on your teeth, STP® Gas Treatment and Fuel Injector & Carburetor Treatment help keep harmful deposits from building up in your engine's fuel intake system, including fuel injectors and carburetors. It is important to keep your fuel system free of deposits in order to maintain maximum performance. These STP® products do not remove existing deposits. See similar questions...

Diesel fuel quality is declining throughout the world, and we expect the trend to continue. In fact, a recent survey suggests that 70% of diesel fuel sold at service stations does not meet the SAE standard for diesel fuel lubricity. The three leading factors are: - crude oil sources, - refining techniques, and - blending techniques. See similar questions...

It is advised that Residuumsol: Fuel Oil Additive be added to the main storage tank just before fresh fuel is transferred to it because the agitation caused by the transfer of the fuel to the tank is enough for the additive to get homogenously mixed in the fuel oil. See similar questions...

STP® has specially designed products for diesel engines and has labeled them as diesel products. They have been thoroughly tested in specific diesel applications. See similar questions...

STP® oil and fuel additives have been specifically formulated for use in four-cycle gasoline engines. Extensive testing in these engines has covered a broad range of passenger car usage and has clearly demonstrated the value of our products in these applications. However, we have not evaluated the performance of our products in two-cycle engines. Therefore, we do not currently recommend that they be used for two-cycle applications. See similar questions...

Testing has confirmed that biodiesel can provide sufficient levels of fuel lubricity, even at blend levels below 1%, in current on-road diesel fuel. Testing is underway to determine specific blend levels that would be required in ultra-low sulfur diesel fuel (15 ppm). Replenishing the loss lubricity that will be apparent in future diesel fuel can be accomplished with conventional lubricity additives either on the market today or in the process of being formulated. See similar questions...