Frequently Asked Questions

Will STP Diesel Fuel Treatment void my vehicle’s warranty?

No, these products have been thoroughly tested to not only deliver superior performance, but also prevent any harm to your vehicle.

Does this product meet the standards of ultra-low-sulfur diesel?

Yes, this product qualifies for the USA EPA 40CFR80.591A Certification, meaning it contains less than 15 ppm (mg/L) sulfur.

Does the Low-Temp Formulation work even if the fuel has already started gelling?

This product will not inhibit wax crystal growth if gelling has already begun. It is recommended that the product be added 5-10°C above the cloud point of the fuel.

What is the shelf life of your products?

STP Diesel Fuel Treatment products can be stored up to 24 months at ambient temperature.

What are the benefits of boosting cetane?

Cetane number is a measure of ignition delay. Introducing a cetane booster produces free radicals that initiate combustion quicker than normal. This will lead to lower engine noise, lower exhaust emissions, and improved starting at low temperatures.

Is STP Diesel Fuel Treatment effective in biodiesel blends?

Yes, STP Diesel Fuel Treatment will effectively treat biodiesel blends containing up to 10% biodiesel (B10).

How often can these products be used?

STP Diesel Fuel Treatment can be used every time you fill up. We recommend to use one bottle to clean up the first tank (64 oz. to 150 gallons) and a 1/2 bottle at every fill up (32 oz. to 150 gallons) to keep your vehicle running in peak condition year round.

Is this product safe for use in gasoline engines?

This product is specially formulated to meet the unique needs of diesel engines. It is not recommended for use in gasoline engines.

How is the Low-Temp treatment different from the regular version?

The Low-Temp treatment contains additional additives that help battle the harsh conditions of the winter months. This includes a Cold Flow Improver, Pour Point Depressant, and Deicer additive that allow diesel fuel to flow in low temperature conditions by preventing and modifying wax crystals.

Is this product safe for use with the newest changes in diesel technology?

Yes, STP Diesel Fuel Treatment has been rigorously formulated and tested to treat internal “sticky” injector deposits as well as traditional coking deposits in high pressure common rail (HPCR) engines. These products meet the latest DW-10 performance standards.