STP® Diesel Exhaust Fluid


STP® Diesel Exhaust Fluid (DEF) is a highly pure, non-toxic operating fluid for newer diesel engines equipped with Selective Catalytic Reduction (SCR) technology. With regular use, STP DEF reduces nitrogen oxide gases during combustion into harmless nitrogen and water emissions.

Formulated To Help

  • Reduce harmful emissions*

Regular Use Helps: 

  • Reduce harmful emissions


1. Push in tab and tear at perforation.

2. Reach into package and remove hose.

3. Pull out spout and push down into opening.

4. Attach the hose by sliding onto the tap until it clicks into place.

5. Position package onto stable vehicle surface.

6. Extend hose to desired length and place into the DEF tank opening.

7. Turn the spout lever to dispense DEF.

8. Turn off spout when full.

Do not overfill the DEF tank. When fluid reaches top of fill pipe, stop filling.




STP® DEF makes replacing fluid easy with its fast filling, no-mess flow spout and hose delivery process.

Official Diesel Exhaust Fluid of Richard Petty Motorsports


Take Note: 
STP® DEF is to be dispensed in a separate DEF tank on the vehicle, not the diesel fuel tank. To store leftover fluid, clean the tube and place in the box to avoid system contamination. Keep away from direct sunlight and store between -10°C (14°F) and 30°C (86°F).