Diesel Exhaust Fluid

Question

We will be going into a diesel shortly and needless to say there are new things to learn. The new units have the DEF tank which holds about 13 gallons. In checking around the price of Diesel Exhaust Fluid varies by several dollars a gallon on brands that I have never heard of. Are there different qualities of this product? Is there anything to be aware of regarding this product? Does it get old in the tank? Should one only put in a few gallons at a time? My thought is to just keep it topped off.
Thanks in advance.

robatthelake · Answer

It's all the same! Regardless of whatever "Brand" You buy it all does exactly the same thing!

lryrob9301 · Answer

I purchase DEF in bulk at the truck diesel pumps, basically DEF is DEF however you purchase it, and is significantly cheaper there than in the 2 gallon containers. My MH has a DEF guage on the dash and the tank only has to be refilled every 6000-9000 miles or so. DEF has a shelf life of about 24 months depending on heat and humidity.

The truck stop DEF pumps are located on the left side of the lanes while MH def tanks on 2010-2013 units are located on the right. 2014 MH DEF tanks are being located on the left now.

bb_tx · Answer

Fill it up. A full tank on mine goes around 7,000 miles. For that many miles you will be spending around $2,000 or more dollars for diesel so a few dollars per DEF brand makes little difference.

bluwtr49 · Answer

There is nothing magic about DEF, basically Urea and DI water.  In a pinch one can probably make it themselves quite easily.

nhirish · Answer

DEF degrades in hot weather. How much you should add depends on your location and how much you drive. If you have your rig parked in FL for most of the year, you might think twice about filling her up!

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Diesel Exhaust Fluid

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