Aftertreatment/Diesel Exhaust Fluid (DEF)

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625-1658: Diesel Exhaust Fluid (2.5 G)

DEF - Diesel Exhaust Fluid

652-3018: Diesel Exhaust Urea Fluid

Cat® Diesel Exhaust Urea Fluid reduces nitrogen oxide emissions in diesel engines by converting harmful gases into harmless nitrogen and water

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This part is designed to fit your Cat equipment based on the manufacturer’s specifications.

Any changes to the manufacturer’s configuration might result in the product not fitting your Cat equipment. Please consult your Cat Dealer before purchasing to ensure that this part is appropriate for your Cat equipment in its current condition and assumed configuration. This indicator cannot guarantee compatibility for all parts.

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Remanufactured

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Products

Aftertreatment/Diesel Exhaust Fluid (DEF)

What is Diesel Exhaust Fluid (DEF)?

Diesel Exhaust Fluid (also known as AUS 32 and commonly referred to as AdBlue in Europe, Australia, and New Zealand) is a solution of solid urea dissolved in deionized water to produce a concentration that is 32.5% urea and 67.5% deionized water.

How DEF Works

Controlled amounts of the DEF solution are injected into the engine exhaust stream prior to the SCR catalyst. The temperature of the exhaust converts the urea in the DEF to ammonia. The ammonia and NO_x in diesel exhaust react in the presence of the SCR catalyst to convert the NO_x into nitrogen (N₂) and water (H₂O).

Typical properties of a DEF solution with 32.5% urea

Property	Typical Value
pH	9.5
Kinetic Viscosity at 25°C	1.28 cSt
Surface Tension at 25°C	65 mN/m, min.
Heat Capacity	0.82 BTU/lb (°F)
Vapor Pressure Factor (relative to water)	0.88

Caterpillar offers DEF in 2.5 gallon (9.5 liter) bottles for single use applications and in semi-bulk quantities 264 gallon (1000 liter) totes.
Any commercial DEF that meets the ISO 22241-1 specification is allowed for use in Cat® SCR equipped vehicles.

Contact Your Dealer

Reference

Fluid Recommendations:

How DEF Works

Typical properties of a DEF solution with 32.5% urea

Property

Typical Value

9.5

Kinetic Viscosity at 25°C

1.28 cSt

Surface Tension at 25°C

65 mN/m, min.

Heat Capacity

0.82 BTU/lb (°F)

Vapor Pressure Factor (relative to water)

0.88

Caterpillar offers DEF in 2.5 gallon (9.5 liter) bottles for single use applications and in semi-bulk quantities 264 gallon (1000 liter) totes.

Any commercial DEF that meets the ISO 22241-1 specification is allowed for use in Cat® SCR equipped vehicles.