DEF in diesel SCR systems.
Modern diesel engines require the use of DEF fluid to meet the clean air standards. I tow with a 98.6 Dodge Cummins powered truck, thus no DEF is necessary. But those who have the newer versions of Di...
Forum Discussion
Slownsy wrote:
Ok what about when it sits in a truck over a long period of time at high temps 80-90 or more.
Frank.
First of all, the storage temperature is based on the average daily temperature, not the high temperature. I'm attaching an article below that goes into a lot of detail on this. But here is a key example from the article:
"EXAMPLE: In 2009 the two hottest months in Phoenix Arizona were July and August. The average temperature for both months was 95oF (35oC), according to the data from the National Weather Service. The average daily temperatures for these months ranged from 104oF (40oC) to 85oF (29oC), while for
some days daily highs reached 115oF (46oC). For areas that see these average temperatures DEF shelf life would be 6 months."
Secondly, even though the DEF starts to degrade, it does not necessarily mean that it has to be drained and replaced in the vehicle. When the concentration goes below 32% Urea, the only adverse effect is higher usage. If the concentration goes below the calibration point for the system, you'll get a warning on your dash that indicates the DEF needs to be replaced. This is very unlikely, and would only happen if the vehicle was stored for an extended period of time in very high average temperatures.
DEF Shelf Life Article
Jim
