DEF diesel engines

[kgard1225]

Hi, I was looking at a few used DPs and noticed one was listed as non- DEF engine. Can I get some opinions on the advantages or disadvantages of getting an older non-DEF engine ? I am only slightly aware of this DEF thing but assume it has to do with the ultra low sulpher fuel. Most of the older coaches seem to have lower HP and I am a little nervous about lack of power after reading many posts about 40 ft DPs with 300- 350 HP engines being under powered. Thanks, Ken

[Passin_Thru]

Actually the DEF fluid is Urea which turns to Ammmonia when heated which crystalizes in your lungs when you breather it so 20 years from now the Govt is gonna go OOOPSY!

[moisheh]

carringb: I think you are confusing HD trucks and RV's. Class 8 trucks use a more robust DPF system. They also have many more regens. In one year a Class 8 truck will travel 150,000 miles. A MH might go 7 or 8,000. At that rate an RV DPF would be more than 20 years old before needing any emission repairs. Navistar is a whole other story as the engineers were arrogant and dumb. They insisted they had developed a system that would be better than the Cummins unit. Of course they were lying! The Navistar engines were and are junk ( mF13 and up). Early Cats with DPF's are just as bad. Our 08 Dynasty ith an ISL has about one regen per year! Still as strong as ever. I might add that emission problems will get worse very soon. The EPA, CARB and impossible to obtain fuel mileage demands from the Gov. will cause nightmares.

Moisheh

[carringb]

Mr.Mark wrote:
Carringb, our 2008 Monaco Dynasty had the Particulate Filter and no DEF which was the second year that the PF was required.

We drove our 425 HP Cummins for almost 70,000 miles in 7.5 yrs. No problem with the Particulate Filter as it would run a regen cycle about every 8K-10K miles. At 40,000 lbs., we averaged about 7.5 mpg's.

I think if I were looking at coaches in that time frame, I would look at the history of that particular coach/engine and then make my decision. I wouldn't just rule them out automatically.

MM.

The Cummins DPF was quite a bit more reliable than the Navistar engines with DPF. But some still had issues. I would trust a high-milaege Cummins with known history. If anything, high mile coaches are driven longer and harder typically, which is actually better for your DPF. When our DPF trucks started having issues (especially with the turbos) we changed company policy to "drive it like you stole it" and overall operating costs went down. Driving too gently causes frequent regens, which uses more fuel than driving it hard!

[J-Rooster]

Ken, one advantage to a non DEF engine in Winnebagos is there is room for a basement heat pump. The Winnebagos with a DEF system used the area where heat pump basement is for a DEF tank and moved there A/C system to the roof top! Great Question!

[Ivylog]

To connfuse things even more, Moaco bought up a bunch of extra 06 engines... I've seen 09 MHs with a 06 engine.
If you ever need a new Partical Filter... hang on to your wallet although less of a issue for a MH that will not see much over 150K miles.

[usersmanual]

Mr.Mark wrote:
Carringb, our 2008 Monaco Dynasty had the Particulate Filter and no DEF which was the second year that the PF was required.

We drove our 425 HP Cummins for almost 70,000 miles in 7.5 yrs. No problem with the Particulate Filter as it would run a regen cycle about every 8K-10K miles. At 40,000 lbs., we averaged about 7.5 mpg's.

I think if I were looking at coaches in that time frame, I would look at the history of that particular coach/engine and then make my decision.

MM.

I agree my 425 Isl works just fine and I know a lot of people with 2008=2009 isl,s and no one has any problems

[Mr_Mark1]

Carringb, our 2008 Monaco Dynasty had the Particulate Filter and no DEF which was the second year that the PF was required.

We drove our 425 HP Cummins for almost 70,000 miles in 7.5 yrs. No problem with the Particulate Filter as it would run a regen cycle about every 8K-10K miles. At 40,000 lbs., we averaged about 7.5 mpg's.

I think if I were looking at coaches in that time frame, I would look at the history of that particular coach/engine and then make my decision. I wouldn't just rule them out automatically.

MM.

[carringb]

Avoid 2008+ diesels which do not used DEF. These will use heavy EGR instead to meet emissions. These are the problem motors. Any of the DEF-euqipped diesels are fine, as are any diesels pre-2008 (beware that some late 2007 diesels may have 2008 emissions... avoid those too).

[usersmanual]

kgard1225 wrote:
What year did they switch to DEF ?

the clean burn diesels came out on 2007 through 2009 approximately and then the DEF engines where u actually add fluids started around in the 2010 area
I think the systems where u add the fluid is better than the 2007-2009 clean burn ones.They had the DPF systems and when they go bad its expensive. Mufflers are like 3800$

[naturist]

kgard1225 wrote:
What year did they switch to DEF ?

2007, but because those engines ALSO required Ultra Low Sulphur Diesel fuel, which was not available, there are almost no 2007 diesels on the roads. Such as there are were probably imported by an individual.

Engines that require DEF will be newer and this most likely have fewer miles on them. Adding DEF is neither difficult, nor onerous, nor for that matter expensive. It is made of two of the cheapest industrial chemicals known to mankind, so whatever you pay for it, the cost is nearly all profit for somebody.

All the engines that use it also have a warning the computer pops up to alert you to refill. On my SUV, the warning is "DEF required, 999 miles until engine will not start." Since DEF is available all over the place, there is no place you can possibly go such that you can't get some DEF within 999 miles.

The prices I've seen range from a little over a dollar a gallon to $17 a gallon, and since the DEF recipe is defined in law, one brand is exactly the same as any other, so buy the cheapest you can find. Adding it is simple. If you can physically put gas/diesel in the fuel tank, you can add DEF.

As others noted, it allows engines to be tuned to deliver more power at greater economy while cleaning up the air we all breathe. Who can oppose that?

My SUV, again for example, has a 6 gallon DEF tank, and that is supposed to carry you 12,000-15,000 miles. Last jug of it I bought cost me $6.95 for 2.5 gallons. At that rate, it's about 1/10th cent per mile. You be the judge whether you can afford that.

[Two_Jayhawks]

No disadvantages of going with an older non DEF diesel. Only disadvantages with a newer DEF diesel is the after treatment system made engines more expensive and that cost is likely rolled into whatever chassis/coach you are looking at.

[kgard1225]

What year did they switch to DEF ?

[JumboJet]

wolfe10 wrote:

JumboJet wrote:
DEF is introduced in the exhaust stream and has no effect on engine power.

While the statement is true, it may be a little misleading.

Because of DEF, the engines can be tuned for more power and better economy.

Very similar to what happened to gasoline vehicles between 1974 and 1975 when catalyst converters were added.

I was referring to the post title "DEF diesel engine". The engines are designed for leaner burn but produce a nasty exhaust that the fluid converts to water and nitrogen via the SCR.

Are the newer engines that require DEF actually providing better economy or just tuned for more HP?

[Jim]

Don't know about DEF, but the rule of thumb for engine size vs RV weight is a minimum of 1 HP/100 lbs. HP = GVWR/100. So if you have a 33,000 lb RV, the LEAST you'd want in engine size is 330 HP. Seems to me of the rigs I've driven, that rule of thumb is fairly accurate.

[wolfe10]

JumboJet wrote:
DEF is introduced in the exhaust stream and has no effect on engine power.

While the statement is true, it may be a little misleading.

Because of DEF, the engines can be tuned for more power and better economy.

Very similar to what happened to gasoline vehicles between 1974 and 1975 when catalyst converters were added.