Prime Guard Diesel Exhaust Fluid (DEF) 1 Gallon — ULTRAPURE, ISO 22241 & API Certified

Prime Guard PRIM00203 ULTRAPURE Diesel Exhaust Fluid (1 gallon) is a high-purity, ISO-compliant DEF formulated for diesel engines with Selective Catalytic Reduction (SCR) systems to support emissions control and reliable operation.

Keeping an SCR-equipped diesel vehicle running cleanly depends on using a DEF that matches strict purity and concentration requirements. Prime Guard’s ULTRAPURE DEF is blended to meet ISO 22241, AUS 32 and DIN 70070 standards and carries API certification, giving technicians and drivers confidence it will work with onboard dosing systems without introducing contaminants that can harm injectors, pumps, or catalysts.

How does Prime Guard ULTRAPURE DEF fit into my vehicle’s emissions system?

DEF is a non-flammable aqueous solution of urea used by SCR systems to convert NOx emissions into harmless nitrogen and water vapor. Prime Guard’s formulation is ultrapure and formaldehyde-free, designed to feed safely through dosing pumps and injectors for predictable reductant delivery.

• Precisely blended to 32.5% automotive-grade urea in deionized water
• Meets ISO 22241 and related regional standards for purity
• API certified to support proper SCR performance and compatibility

Will using this DEF affect fuel economy or maintenance?

DEF itself doesn’t burn in the engine, but it enables the SCR system to reduce NOx efficiently, which helps the engine run closer to its optimal combustion settings. That can translate to stable fuel economy and potentially lower maintenance costs by avoiding SCR-related component contamination.

• Helps maintain SCR efficiency so engine calibration stays optimized
• Ultrapure ingredients reduce risk of deposits and sensor fouling
• API certification reduces uncertainty about long-term compatibility

How should I store and handle a 1-gallon container of Prime Guard DEF?

Store DEF in a cool, dry, shaded area away from direct sunlight and temperatures below -11°C (12°F) to avoid freezing. Use clean pouring tools and avoid cross-contamination with fuels, oils, or other chemicals to preserve product integrity.

• Keep sealed when not in use to prevent airborne contamination
• Avoid long exposure to heat or sunlight to maintain stability
• If frozen, thaw slowly at room temperature before use—do not heat

How can I tell this DEF is the right quality and concentration?

Prime Guard ULTRAPURE DEF is manufactured and tested to meet international standards for urea concentration and impurity limits. Look for ISO 22241 compliance and API certification on the label as confirmation the product matches the specifications required by SCR system manufacturers.

• 32.5% urea concentration for consistent dosing accuracy
• Meets ISO 22241, AUS 32, and DIN 70070 purity criteria
• API certification indicates quality controls and testing procedures

Who is this for: Prime Guard PRIM00203 ULTRAPURE DEF (1 gallon) is intended for owners and fleet managers of light- to heavy-duty diesel vehicles equipped with SCR systems who want a dependable, standards-compliant DEF in a convenient size. It’s suitable for technicians topping off onboard tanks, drivers carrying spare fluid for long routes, and service departments that require consistent product quality. Avoid using DEF that is contaminated or of uncertain origin; using a certified, ultrapure solution helps maintain SCR system reliability and reduces the risk of costly repairs related to improper reductant.