what happen when you run out of DEF?

I don't think it would damage the engine itself. Maybe the SCR catalyst.

I should shoot Witchinghour a PM and get him to answer this.

 

I don't have DEF. How often do you need to fill that tank or what is the rate of consumption? Has anyone figured a mpg for it?

 

I just fill it every third fill up. Never below half tank and think my truck gets 3000 to a tank.

 

It depends. My truck usually gets about 3400-3600 miles per tank. I think that's roughly 270-280 miles per gallon.

Unless my math is off that's roughly $.01 per mile in added operating costs if you use strictly bulk DEF averaging $2.95/gallon.

 

LOL that was good

 

How do you come to that conclusion? DEF has nothing to do with the engine - on the contrary, you don't want that stuff anywhere near moving parts. When I change a DEF filter, I use a 1-1/16" combination wrench rather than a ratchet because, if that stuff gets on a ratchet, and you don't get it 100% cleaned off immediately, it will seize up your ratchet. So you can imagine how detrimental it would be if that stuff actually went through the engine - and it doesn't.
Exhaust leaves the engine, goes through the DPF, then exits the DPF and goes to the DEF doser... that's where it gets sprayed with DEF, and there are no moving parts involved here... after it's dosed, it goes through the SCR and out into the wild blue yonder.
Running out of diesel exhaust piss won't cause you to have to rebuild anything.

 

My last company used DEF and the trucks that had it had a 4 gallon tank that would last around 4000 miles.

 

In the Volvo I drive if it runs out of DEF it will not go faster than 5mph.

 

$.01 - $.02cpm is the expense for DEF. At least that is what I have calculated it out to be in a variety of different trucks and situations.

Kind of surprising it is that high. Almost as much as tires.

 

What kind of Truck?

'My' Cascadia has around a 13 gal tank.