Dodge cummins 5.9 or 6.7 ?

Kennedycamper wrote:
I'm looking to buy a newer truck for hauling a 5th wheel. For those who have had both 5.9 & 6.7 engines, which do you think is better and why? Right now I'm leaning towards the 5.9, because it has a lot less pollution **** on it. Truck will probably be a 2005 to 2009. Opinions?

Having owned just the 6.7, and from just a power standpoint , I would go the 6.7 for towing fifth wheels

Gee I wonder how many times we are going to hear "pollution cr@p" or "emmisions garbage" in this thread? Especially from those who don't even kow why these devices are on their truck in the first place.

06-7 was probably the best of the 5.9s. But they still lacked exhaust brake and the wonderful 6 speed auto. We bought new an early 6.7, and it is a towing beast. No problems with emissions what so ever other than a couple of software updates early on. If I do encounter emission issues will be when I do the deletes and keep on truckin

Yes my biggest fear is the DPF, and I'm not really wanting to do any deletes.

Emissions Reading

I was leery of the emissions setup on the pre-SCR 6.7s because of excessive EGR and DPF regens. I think the newer ones just run a lot cleaner with the addition of DEF, and get better mileage too.

Now you're comparing the early 6.7 to the 5.9, which is a whole different question. The newer trucks are nicer, have more power and a 6 speed, but the emissions are more problematic. If you aren't in an emission testing area you do have the option of deleting a 6.7 to avoid those issues, but there are legal and environmental drawbacks to that. Nonetheless, a lot of guys do it once out of warranty. VW even does it for you without voiding the warranty...

If you go with the 6.7, you will get less regenerations and better mileage with the ones that treat the exhaust with diesel exhaust fluid (DEF). I would avoid the engines that had diesel particulate filters (DPF) and did not treat the exhaust with DEF - I feel this was a transition period that is more problematic due to partially applied emission systems that are more prone to ashing/sooting.

I had both, an '07 with the 5.9 and now an '11 with the 6.7 none DEF. Never had a problem with the '07 but the soot it put out under load. After many mile pulling my trailer through the mountains the side of my trailer was covered in soot and some made it's way into the trailer from the slide. Got about 13 mpg towing. However.....The 2011 is another animal...The creature comforts, there is no comparison. Not to mention the 6 spd. tranny and the exhaust brake. It gets about 11 mpg. towing. Runs real clean and puts out no soot at all. I have no plans to delete anything as long as there is no problems and under warranty.

Kennedycamper wrote:
Yes my biggest fear is the DPF, and I'm not really wanting to do any deletes.

Your biggest issue will not be the DPF. It would be the EGR system if you do not maintain the truck properly especially if you idle a lot or do mostly low load driving. If you do those two things often then I would have the EGR system cleaned out sooner at around 100k miles.

Although the EGR system on the 2007.5-2012 6.7L was really working over time because it met the 2010 NOx emissions back in 2007 without the use of an SCR/DEF system. The fact that it was the only thing on the truck that removed NOx, then it was constantly working which would clog up EGR coolers and DPFs quickly.

The new 2013 and up engines with the SCR/DEF system utilize the EGR a lot less because the SCR/DEF took over the job of removing NOx at higher loads. It is only being used in low load situations and the SCR/DEF takes over after that as the primary device that removed NOx which greatly reduces how often the EGR is being used.

Kennedycamper wrote:
I'm looking to buy a newer truck for hauling a 5th wheel. For those who have had both 5.9 & 6.7 engines, which do you think is better and why? Right now I'm leaning towards the 5.9, because it has a lot less pollution **** on it. Truck will probably be a 2005 to 2009. Opinions?

I would suggest the following, unless you live in the rust belt.

Exhaust brake on current 5.9
Small chip on Current 5.9
DD clutch
Then enjoy the tow!

I can't afford a 2013, so that's not a choice. I don't drive the truck much when not pulling the trailer, but do make sure it gets driven at least once a week. My choice is between an 05 to 07 5.9, or a 07 to 09 6.7.