What is Diesel Exhaust Fluid (DEF)?

Diesel Exhaust Fluid is a non-flammable fluid comprised of 33% Amonia Based Urea and 67% Purified Water.  DEF is used with diesel engine exhaust systems to reduce the amount of emissions produced by turning Nitrogen Oxide (NOx) into nitrogen and water vapor.  DEF Technology has been used in diesel engines in Europe and has a proven track record.

How often do I have to fill my DEF Tank?

The SCR system uses DEF at a rate of about 1 to 1.25% of the vehicle's diesel fuel usage.  A full tank of DEF (20 Liters) provides a driving range of about 8000 Kilometers.  DEF usage is directly related to fuel consumption, so range can be affected by the type of driving and conditions.

Where can I purchase DEF?
DEF is available at all GM Dealers and most major truck stop chains.  Competition Chevrolet offers DEF Fluid in the following sizes:

3.78L (1 US Gallon)- $12.25
(GM PART# 88862660)
9.46L (2.5 US Gallons)- $21.35
(GM PART #88863524

DEF Fluid can be purchased in our Parts Department at (780) 963-8999.

How Do I Refill My DEF Tank?

DEF is stored in a 20 Liter (5.3 US Gallon) Tank located under the passenger side of the cab.  The DEF tank fill point is located under the hood on the passenger side of the cab.  It is identifiable with a Blue Cap.

How do I know when my DEF tank is low?

The Chevrolet Silverado has an Electronic Onboard Warning System that will provide a message that alerts the driver when the DEF level is low and has a remaining range (at current rate of usage) of 1600 Km.  Additional messages will alert the driver at the 500 KM, Low, and 0 Km ranges as the DEF Tank gradually empties.

What happens if I run out of DEF?

If the DEF Tank is allowed to run empty, the Onboard Warning System will alert the driver.  If fluid is not added at the next vehicle start, the vehicle speed will be reduced to a maximum of 90 Km/Hour and ultimately to 5 Km/Hour as per Federal and Provincial Government Guidelines.

My vehicle speed has been reduced to 5 Km/Hour.  Do I have to bring it to the dealer to have it repaired?

Your DEF Tank is empty.  Add at least 3.78L of DEF Fluid to release the vehicle from any speed limitation.  Once the system is refilled, the system resets itself and a service visit is not required.  It may take up to 30 seconds in park and/or several KM of driving to update the DEF level warning.

Does DEF Fluid Freeze?

DEF does freeze, at approximately -11 Degrees Celsius.  If the DEF is frozen, the vehicle will start as it always has.  After the engine is started, the DEF Tank and Lines will thaw as they are electrically heated to ensure adequate DEF delivery in cold weather.  The quality of the DEF does not change if it is frozen and then thawed.

I've heard lots of negative things about the new DEF Exhaust Fluid System in the new GM Diesel Trucks.  What has GM changed?

GM has made two calibration changes to the DEF System in response to the issues that developed this winter.

1) The first calibration enhancement was phased in at the end of December 2010.  This enhancement extended the heating cycle to defrost the DEF.  The original cycle was a 90 minute cycle which has now been increased to a 270 minute cycle.

2) The second calibration enhancement was phased in at the end of January 2011.  This enhancement addresses the level of DEF in the system that is associated with reduced performance initiation.  The previous program would put the vehicle into reduced power mode due to the system detecting a lack of DEF fluid due to environmental factors.