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Delacroix · 04-26-2016, 02:28 PM

I'll be picking this coach up this weekend. My current coach has a Navistar engine that does not use urea. I questioned the dealership about possible DPF problems and they acted as if it was absolutely no concern. Does the filter tend to clog up on this coach? Do you have to be careful and not sit and idle much. If you sit and idle with my current coach it's the kiss of death. What can people share about the 2013 Mountainaire using urea? About how often do you need to fill up the urea? It appears to me that it is not convenient to fill the urea at a truck stop. It looks like the hose at the pump won't reach the fuel and the urea with moving. How do people do this? I figure it's easier to learn from others in advance.

Terry43 · 04-26-2016, 02:39 PM

Quote:

Originally Posted by Delacroix

I'll be picking this coach up this weekend. My current coach has a Navistar engine that does not use urea. I questioned the dealership about possible DPF problems and they acted as if it was absolutely no concern. Does the filter tend to clog up on this coach? Do you have to be careful and not sit and idle much. If you sit and idle with my current coach it's the kiss of death. What can people share about the 2013 Mountainaire using urea? About how often do you need to fill up the urea? It appears to me that it is not convenient to fill the urea at a truck stop. It looks like the hose at the pump won't reach the fuel and the urea with moving. How do people do this? I figure it's easier to learn from others in advance.

I have a 2011 DSDP with DEF and have not had any problems. I bought a Blue DEF 2-1/2 gal at Auto-zone and just refill at truck stop after fueling up and do not have to move coach. Pour in DEF tank when I stop for night, it is helpful if you buy a long neck funnel. The rule of thumb I have heard is one gallon of DEF to each 100 gallons of fuel.

loisjop · 04-26-2016, 02:45 PM

The Cummins 450 isl will run around 300-350 miles per gal of def. The 600 isx slightly less than 200 miles per gal.

EZDZIT · 04-26-2016, 03:00 PM

I have not yet attempted to use the DEF truck stop pump as our 2013 DSDP has the filler on the wrong (passenger) side. Truck stop DEF is much cheaper - about $2.50 per gal vs. $12 for 2 1/2 gallons at Walmart and higher at auto parts stores. We, too, have had no problems with the DEF system. I estimate that we are using even less than 2% compared to the fuel consumed. I read somewhere in these threads that the DEF fluid filter is good for 200,000 miles.
We do not idle our coach unnecessarily only enough to bring the air and oil pressure up plus a couple minutes and then ease through the campground. After a hard pull followed by the need to shut down we will idle for several minutes to cool so as not to cook the oil in turbo. I have never seen the regeneration lights come on in our 33,000 miles of ownership. A Freightliner rep told me with our vast majority of highway miles, I should never have to do a manual regeneration.
By the way, if buying at Walmart (or anywhere) be sure the DEF has not been tampered with by checking the jug seal.
Hope this helps and I am interested in any other experiences.

lllkrob · 04-26-2016, 03:29 PM

Quote:

Originally Posted by Delacroix

I'll be picking this coach up this weekend. My current coach has a Navistar engine that does not use urea. I questioned the dealership about possible DPF problems and they acted as if it was absolutely no concern. Does the filter tend to clog up on this coach? Do you have to be careful and not sit and idle much. If you sit and idle with my current coach it's the kiss of death. What can people share about the 2013 Mountainaire using urea? About how often do you need to fill up the urea? It appears to me that it is not convenient to fill the urea at a truck stop. It looks like the hose at the pump won't reach the fuel and the urea with moving. How do people do this? I figure it's easier to learn from others in advance.

First, the term is D-E-F Diesel Emission Fluid.

If your DEF tank is on the driver's you can fill at the truck stop pump. There are two hoses, one for diesel fuel, a second smaller hose in an enclosed compartment usually to the right of the pump that holds the DEF nozzle. You would have to move your coach forward some to align with this hose to fill your DEF tank, or you can do a Terry43 suggested and buy a container to hold a few gallons and fill it at the pump and add it later to the tank. That's what I do on my Pheaton with the tank on the passenger side.

As to consumption, your engine will burn approximately 1.5 to 2.0 gallons of DEF for every 100 gallons of diesel. Your DEF tank will hold around 12 or 13 gallons, so you can drive a long time on one DEF fill.

DEF has no effect on the idling of the engine. As Cummins has stated in it's manuals prolonged idling is neither required nor good for todays diesel engines. One advantage you will find is your exhaust pipe will remain clean inside, no black soot buildup and no exhaust black streaks on your toad if you pull one.

Mr JP · 04-26-2016, 05:33 PM

We have a 2011 MADP and have no problems with the def system. When the def gauge in the dash gets down to about 2 green bars I start to look at the truck stops that are not busy and I just fuel up and then spin around and fill up with def and it takes about 6 gallons. I have bought from Walmart but as mentioned be careful to check the seal has not been broken, people use the def and refill the jug with water and return it to the store.
Good Luck
JP

snickers · 04-26-2016, 06:18 PM

We have a 2014 MA and when we leave home with the tank full we can go 1500 miles without filling the Def it is cheaper to buy at truck stops or bulk. Since we used it on the farm in a lot of our equipment and trucks we have it in bulk from our supplier. Then when I need some on the road I buy it at walmart

bitubo · 04-27-2016, 09:00 AM

Regarding the DPF, AFAIK, it takes over 100k miles before it becomes a concern in most cases.

slabman · 04-27-2016, 10:19 PM

My 500 hp isx gets me about 250 miles per gallon of def. Because it's too difficult to try filling at a truck stop ( and the fact that I rarely even go INTO a truck stop), I buy def from Walmart in a 2-1/2 gal. blue jug of their house brand for $7.88. Sometimes they only have Blue DEF on the shelf, so you may need to ask if they have more in back.

Mr_D · 04-27-2016, 10:28 PM

Quote:

Originally Posted by bitubo

Regarding the DPF, AFAIK, it takes over 100k miles before it becomes a concern in most cases.

Ours has been replaced twice in 45,000 miles but we don't have DEF either. The last time the DPF cracked and couldn't be repaired and no rebuilts were available either.

andyh · 04-28-2016, 06:41 AM

Just to clarify, starting with the 2007 engines Cummins used Diesel Particulate Filter (DPF), Exhaust Gas Recirculation (EGR) and Variable Geometry Turbo to meet the 2007 emission control requirements. 2010 they added Diesel Exhaust Fluid (DEF) to control nitrogen oxide emission. All 2010 and later Diesel engines in the US are using this emission control configuration with the exception of the now discontinued Navistar engines.
Some 2007 engines used in 2008 motorhomes had problem with cracked DPF elements and other emission control related component reliability such as EGR coolers before they reached 100000 miles. I think most of those initial problems have been solved by 2010, since all highway trucks are using the same system. The DEF addition seem to be quite reliable. Problems I heard of were related to people buying bad DEF in stores.
I fill my DEF tank at Pilot / Flying J truck stops most of the time using a 2.5 G jug. Sometimes, when traffic is light I pull forward and use the pump on the next lane on the right to fill the DEF tank.

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