What are the pros & cons?
DEF is in the newer coaches. I would not be afraid of it. In talking with the cummins guys, they said do not put water in there as it will leave mineral deposits. Other than that no issues.
The only issue I see with the def is that you will have to pull forward at the truck stop to bulk fill.
Thanks, John. Yeah, getting bulk DEF at a truck stop seems to be the only real complication. Even though truckers have always been courteous towards me, I always have the feeling that I am in their way. Where else can DEF be purchased in bulk? I don't even know the size of a DEF tank.
This decision for us is really one about age. Of the coach, not us. We want to buy our LAST motorhome, not just our next one. When we bought our current one, we made the mistake of buying too old of a coach. It seems that every trip would cost us another $1000 in unexpected repair bills. They were not issues due to lack of maintenance, but issues of age or maybe just bad luck.
So we are looking at coaches of the years 2005-2009, thus the DEF question.
My pickup uses DEF, not very much, the tank holds 6 gal, and I put in a 2.5 gal jug about every 8-10 K miles, so not a biggie. Have noticed on the new Foretravels, the DEF tank is behind the tag axle, a long way from the diesel filler.
The good part of the DEF as I understand, it does allow more horseower due to the reduced emmisons, now the Cummins ISX can go up over 800 hp, the transmission being the weak link. SO onward and forward, its just money, who is counting ?
DEF in Gallon containers is available at any truck supply house.
Gary B
I guess I'm confused, wasn't 2010 the first model year FT to have a Cummins that required DEF, and then it was mid-model-year? I know we looked at a 2010 Nimbus that didn't have a DEF setup.
Michelle
Maybe you mean DPF? (Diesel Particulate Filter)
I'm not sure when these kicked in (I would guess around 2007-2008)
These are filters that have to regenerate themselves occasionally when they start to get blocked with particulates. Regeneration process involves burning diesel fuel inside the unit to turn the particulates into ash that can blow through. The DPF and exhaust gas gets very hot during the regeneration process.
So John, does that mean you could get by with distilled water or any water for that matter in a pinch? :D
Probably some regulation... maybe like running off road diesel. :P
The big reaon to use windshield antifreeze solution, it does not corrode the nozzels as water does.
Good point! DEF = Diesel Exhaust Fluid, aka the urea-based system.
DEF Overview - discover Diesel Exhaust Fluid (DEF) (http://www.discoverdef.com/def-overview/)
If you use water you will voice the Cummins warranty. They will see the build up of minerals. The washer antifreeze is a better bet or just carry a spare gallon.
The reason i have not tried the window antifreeze yet, is I have no idea if it will work, just think it might , thinking about weaning it down about half & half for a test, from there will see. Hate messing with a warranty and since it costs about $8.00 for 2.5 Gal jug that lasts ablut 8 k miles, either way is not going to break the kitty.
My 2011 Tiffin used DEF. Ran fine got good mileage and no issues in 15k miles. The DEF tank was on the right (passenger) side and I believe almost every coach regardless of manufacturer is like that. Dumb. Where is the bulk DEF pump? On the drivers side of course. I just bought the 2.5 gal plastic containers at Walmart, Flying J, etc. and didn't worry about going in the wrong way at the truck stop. Not a big deal as the mixture ratio is 1 gal of DEF to every 50 gal of diesel so a 12 gal DEF tank will take you a long way.
That said, I don't miss the extra work for the DEF on my 2001 U320. :D