Frequently Asked Questions

Why is Diesel Exhaust Fluid needed?
The EPA has mandated that all Class 8 on-road diesel vehicles manufactured in 2010 must be equipped with systems to reduce NOx emissions.

What is Diesel Exhaust Fluid?
32.5% high purity automotive grade urea and 67.5% water.

Can I mix this fluid myself?
No, the process in which this fluid is mixed is very specific, the on-board system knows if the fluid is out of specification or if there is contamination. Concentrate urea is not available.

Do I change this fluid out, and how much do I need?
Since this fluid is consumed at a rate of 2% of diesel fuel usage, this fluid is re-filled rather than replaced with other engine products such as antifreeze and engine oil. Tanks on board vary in size from 16-50 gallons in larger trucks. The tank must have fluid in it to operate.

How will a driver know when they are low on Diesel Exhaust Fluid?
There are simple warning indicators right on the dash board for the drivers indicating the level of the fluid.

Where do I get Diesel Exhaust Fluid?
Diesel Exhaust Fluid is available in Alabama, Georgia, Tennessee, and the Florida Panhandle through our distribution network.  To place an order, contact Customer Service at 888-802-7500 or email us at customercare@mcphersonoil.com.

What happens if Diesel Exhaust Fluid gets too hot or too cold?
When DEF gets too cold there is no harm whatsoever to the shelf life of the fluid, however it begins to freeze at 12ºF. Trucks will start and the tank will be heated until the solution starts to flow and the driver is on his way. Storage for long periods at high temperatures can reduce the shelf life of the fluid.

Is it possible for a driver to put diesel fuel in his DEF tank since they are so close together?  If so, how can this be avoided?
To avoid this, the industry standard for on-board DEF dispensing holes is smaller than that of diesel tank. The nozzles at fuel islands for diesel fuel will not fit the on-board DEF tank.