Will DEF harm a CUT?

[Topzide]

DEF is used in the exhaust system to lower the Nox and particulate matter. Diesel pickups started around 2010, larger trucks maybe a bit sooner and a lot of tier IV tractors.

Basically it's a form of fertilizer for use in equipment. Some people purchase out of date DEF to put on their fields.

 

[CliffordK]

DEF = Diesel Exhaust Fluid.
It is a mixture of Urea (same stuff as in Urine), and water.

I think it goes into a catalytic converter to clean up the exhaust before it gets to the diesel particulate filter. If you don't have the clean emission stuff,then you don't need it.

I'm not convinced mounting the exhaust pipe so it blows diesel smoke into one's face was the wisest design choice.