I had thought about going a few years newer, replacing my 2006 Holiday Ambassador 40' PLQ.But then I thought about emission equipment such as DPF and DEF engines. What years did manufacturers start using these? I had also heard that Tiffin, among others bought a bunch of earlier engines to forestall the equipment another year or so.Then I started checking other brands--Tiffin-- roof rail replacement and some rotten floor issues.Newmar--fiberglass cracksThen I started getting cold feet. I have had pretty good luck with my rig. Biggest problems were leaks which it took awhile to fix. Roof caulking and driver window regasket, mainly.So should I "hold em" or "fold em"???

I think the 2007 models got the DEF

2007 model ENGINES went to DPF and then to DEF in 2010 model engines.....NOT the same for the RV model year. Monaco purchased a bunch of 2006 Cummins ISL and were still using them in 2008 and a few 2009 models. They also purchased a large amount of Cummins ISM & ISX engines which were still being installed as late as 2012, in the larger coaches.

The DPF was mandated by the 2007 EPA requirement. Any engine built after 1/12007 has the DPF. most coach builders managed to stockpile enough engines to hold off the requirement until the next model year. 2010 was the same story for DEF. Engines built after 1/1/2010 had to meet the requirement. There were some exceptions due to engine builders using credits issued by EPA or by paying a fine per engine sold. Again, coach builders bought up enough inventory of engines or chassis to get through the 2010 model year before using DEF.

Yes, a little more complicated, as not all engines had DEF, even after 1/1/10. Navistar, for example used high amounts of EGR to (attempt to) meet the new EPA standards.But, for most 1/1/10 was ENGINE build date (not chassis or coach) from which DEF systems were fit on the vast majority.Here is a good 1 1/2 minute video on it: http://www.youtube.com/watch?v=uQHvi2Lgnac

When were DPF and DEF introduced on RV diesels?

gerrym51
Explorer II
Oct 29, 2013
Dpf 2007. dpf plus def 2010.

emissions laws dictated this. in 2010 they got even stricter.
Pop-Pop_C
Explorer
Oct 29, 2013
Had a 2011 3500 CHEV Duramax. Took about1 ga. DEF PER 1000 Mi.
Traded for a Winnie 40 U 8.3 Cummins. This gets btwn. 7-800 Mi per gal. Def.
Has not been a issue for us.I just roll with it. Just a part of full timing.
CREATO
Explorer
Oct 29, 2013
Has nothing to do with the rv industry but with the engine manufacturers being able to meet emissions or pay fines and or use credits. it will vary by manufacturer.
kjburns
Explorer
Oct 28, 2013
For our Winnebago, the DEF engines showed up in the middle of the 2011 model year. I get the 2.5 gallon containers at Wally World for $12.
midasman
Explorer
Oct 28, 2013
Thanks mccsix. I have noticed when new diesel pickups go by, I can not smell a
A THING!
mccsix
Explorer
Oct 28, 2013
FYI DEF allows the engine more HP and better mpg and absolutely no diesel smell/smoke out the tailpipe. 13 gals should last 4-5000 miles.
- putergod
  Explorer
  Feb 18, 2025
  I know this is old, but this is so wrong I couldn't help but comment.
  DEF does absolutely NOTHING to help with power or mileage. I would really love to know where you got that caca from...
  DPF and EGR seriously choke a diesel engine making HP and mileage far worse.
  - way2roll
    Navigator II
    Feb 20, 2025
    But before you post another topic, it should be noted that you're wrong. DEF systems generally do not negatively impact MPG, and in fact, can often lead to a slight improvement in fuel economy by optimizing engine performance and reducing the workload on emission control systems, allowing for more efficient combustion; some manufacturers claim a fuel efficiency increase of up to 5% with DEF usage. Now if you totally DEF deleted a truck and re-tuned to run based on the lack of DEF equipment, it might get better mileage. But at what cost? The cost to remove it, the increase in emissions, loss of any warranty and it's illegal in most states and you might get marginal gains. Why bother?
midasman
Explorer
Oct 28, 2013
Thanks, guys.
wolfe10
Explorer
Oct 28, 2013
Yes, a little more complicated, as not all engines had DEF, even after 1/1/10. Navistar, for example used high amounts of EGR to (attempt to) meet the new EPA standards.

But, for most 1/1/10 was ENGINE build date (not chassis or coach) from which DEF systems were fit on the vast majority.

Here is a good 1 1/2 minute video on it: http://www.youtube.com/watch?v=uQHvi2Lgnac
steveownby
Explorer
Oct 28, 2013
The DPF was mandated by the 2007 EPA requirement. Any engine built after 1/12007 has the DPF. most coach builders managed to stockpile enough engines to hold off the requirement until the next model year. 2010 was the same story for DEF. Engines built after 1/1/2010 had to meet the requirement. There were some exceptions due to engine builders using credits issued by EPA or by paying a fine per engine sold. Again, coach builders bought up enough inventory of engines or chassis to get through the 2010 model year before using DEF.
The_Texan
Explorer
Oct 28, 2013
2007 model ENGINES went to DPF and then to DEF in 2010 model engines.....NOT the same for the RV model year. Monaco purchased a bunch of 2006 Cummins ISL and were still using them in 2008 and a few 2009 models. They also purchased a large amount of Cummins ISM & ISX engines which were still being installed as late as 2012, in the larger coaches.