I am getting a new to me 2007 Itasca Horizon DP with the 8.9 Cummins ISL 400hp engine. The EPA 2007 rules required a diesel particulate filter. Was that a requirement on 2008 model year or 2007 engines. Reading the Cummins site doesn't specify. For this who have the DPF installed, do you have any issues with drivability or problems? One note I read said idling was problematic. Picking up the coach in a couple days so haven't had a chance to learn what exactly is in it.

Give Cummins a call with the engine serial number:Cummins 800 343-7357Might also ask if it has an exhaust brake or engine compression brake. The ISL could be ordered with either, with the engine compression brake being much stronger and more $$.

drwwicks, we had a 2008 Monaco Dynasty on a 2007 frame. We had the diesel particulate filter and never had a problem with it. It will go through a regeneration every 8K-10K miles. In the 69,700 miles, ours seemed to hit it about every 10K.You have to use Ultra Low Sulfur Diesel (ULSD) at 15ppm, otherwise, you will clog the system. Low Sulfur Diesel (LSD) is 500 ppm.Mexico does not sell ULSD (from what I understand) so fill up before you go over the border. We never took our coach to Mexico.Many manufacturers bought 2006 engines and put them in later model motorhomes, yours may have a previous emission engine.Our new coach has the particulate filter and the Diesel Exhaust Fluid (DEF) requirement. No problems in 14,000 miles.Safe travels,MM.

Presumably you're asking if your new-to-you coach has a DPF? As stated above, Cummins should be able to tell you, as could Itasca/Winnebago if you call there with the VIN.We have a DPF on our 2014 and have had no problems with it (and hopefully it will stay that way). There was discussion of a poorly-manufactured DPFs cracking and I'm sure you can find that information by Goggling it. Mostly I've read about that happening on Tiffin Breezes, but I don't really pay attention on what other manufacturers might have been effected.Idling isn't a huge issue unless you do it for a long time and the system isn't able to do a regen and burn the soot ouf of the DPF when it needs to. You need to take it up to highway speeds so it can do that. Congrats on your new Itasca.

drwwicks, on second thought, your new coach probably has a 2006 chassis which may very well have the pre-particulate emission engine.I think they called the ISL's with the particulate filter, 425 hp Cummins (I could be wrong). Ours was called a 425 ISL.MM.

5 years ago when I was looking at diesel pushers, it appeared that 2007 motor homes didn't have the dpf and 2008's did.

Cummins 400 ISL diesel particulate filter | Good Sam Community

15 Replies

moisheh
Explorer
Jul 12, 2015
Ivylog: EGR never became standard until around 2002. Anything 2001 and below is no different than a 1995. Truckers buy "Glider" trucks. These are essentially a new truck but come with a pre 2002 emission system engine. No EGR! It is more than just the EGR as the ECM is also set up differently. Now if only we could buy a new MH with that same emission system!

Moisheh
Ivylog
Explorer III
Jul 12, 2015
A slight correction to Lurker's comment: EGR has been required since around 1998.
bullydogs1
Explorer
Jul 12, 2015
My light comes on like once a year on a trip for about 30 to 40 minutes...otherwise, no issues, once in a while I will see the try light but it will go out within a second..no issues running or anything...I do not extend idle for more than 5 minutes.
Lurker1
Explorer
Jul 12, 2015
I have a 2007 40' Itaska Horizon with the Cummins ISL. No DPF, EGR, DEF, etc. I assume yours is the same. Great, reliable engine, but you'll find the side mounted radiator with this year group was manufactured too small, and has trouble cooling when under significant load and when outside temp is high. Provided you manage this appropriately by keeping the RPMs high, you won't have problems.

I've driven some pretty significant passes (Eisenhower, Vail, and numerous throughout California), and can do them all in any outside air temp, but must take it slow and with engine RPM ~2500 when towing and when outside air temp is 90* or greater.

Interestingly, with the Cummins ISL, horsepower has changed slightly over the years as the emissions stuff was added, but torque has always remained the same.
Ivylog
Explorer III
Jul 12, 2015
Look at the exhaust... pretty easy to tell the difference in a muffler and a DPF with all the wires going to it. I even saw a 09 Monaco with a 06 engine in it as they bought up a bunch of 06 engines so they would not have a DPF.
I would not let it be a deal breaker as Mr Mark, said... he did not have any problems out of his.
koda55
Explorer
Jul 12, 2015
Our isl 400 was built December 2006. Our chassis was built March 2007 and our motorhome sold October 2007 and listed as a 2008.
drwwicks
Explorer
Jul 12, 2015
Thanks for the replies. I had DPF in a couple of pickups and a regeneration problem only twice. Once with a new to me 10 Ford and with the 12 Dodge after we had been driving it in town. All things said and done, I hope it doesn't have the DPF, just another PITA to go wrong. I'll check the cosh out on Monday and if I can't figure it out, will call Cummins.
bullydogs1
Explorer
Jul 11, 2015
If it is a 2006 chassis and does not have the DPF...call Cummins with serial number of engine..there was a wrist pin issue where the wrist pin would snap and you were stark dead where it happened.....the recall was so lame (they put a warning light when it was about to happen)...make sure your serial number of the engine was not part of the recall...note many of them did snap within 10000 miles and were replaced under warranty so if that happened here you are good to go.
Ivylog
Explorer III
Jul 11, 2015
You could have a 06 engine in it and if it's advertised as 400HP, not 425 then it probably does not have one. Like MM suggested... call Cummins and ask about it and the exhaust/Jake brake. If it has a switch for HI/Low brake it's a Jake brake.
GMandJM
Explorer
Jul 11, 2015
Is that a Freightliner chassis? If so, you can call them with the VIN. They'd have tons of information.