2010 650 Cummins mileage

That coach is also on the front end of the 2009/2010 emissions systems that Cummins started using. You may want to see what sort of maintenance, if any, was done to the DOC/DPF system. We have a 400/450 Cummins, but my guess is that Cummins used the same DOC/DPF system on all of their OTR engines??

You may also want to have it plugged into the Cummins computers and see what codes may be sitting in the computer and make sure that the injectors are holding up. Bad injectors lead to major dollar problems with the DOC/DPF.

Otherwise, as I was told when I wanted to purchase one of these, if you are worried about the cost of fuel to get from point A to point B, these are not the motorhomes for you!!

I bough mine before reading about the broken #6 valve problem. Not a clear answer as to why nor what to do about stopping it from happening. Too soon to say the new and improved parts will solve the problem or the new engine. Why is this happening mainly in MHs and hopefully only in the 600-650 HP engines?

I was able to get a camera to the #6 intake and it didn’t look any different than the 4 or 5. I am using the “Ugly Fix” and I installed a metal freeze plug in the EGR tube at 46K miles and it now has 56K. At this point all I can do is cross my fingers and hope for the best as we really like this MH.

*OP, NO WAY would I buy a ISX, especially a 600-650 HP. I would keep what you have until a definite cause and cure is guaranteed...not there yet.

Ivylog wrote:
MPG is not even in the ball park of possible expenses on that engine. You need to read these 32 pages on repeated #6 broken valve on the ISX engines: http://www.irv2.com/forums/f123/cummins-isx-broken-valve-in-6-a-401436.html
#6 broken valve
There is a post today on it in a 06 ISX...not sure yet if it was a 600 HP. I have a 06 525 HP that hopefully is not prone to this problem.
http://www.irv2.com/forums/f123/isx-cummins-failure-473121.html
2006 ISX

Good advice. I would buy an new ISX, but not one of the older models.

Thanks for the info Dennis.
Thanks for the links lvylog.

MPG is not even in the ball park of possible expenses on that engine. You need to read these 32 pages on repeated #6 broken valve on the ISX engines: http://www.irv2.com/forums/f123/cummins-isx-broken-valve-in-6-a-401436.html
#6 broken valve
There is a post today on it in a 06 ISX...not sure yet if it was a 600 HP. I have a 06 525 HP that hopefully is not prone to this problem.
http://www.irv2.com/forums/f123/isx-cummins-failure-473121.html
2006 ISX

purplekeenah wrote:
Thanks for the comments, I'm just trying to weigh a number of variables.
Dennis, you probably don't carry a calculator with you all the time, but what would you estimate your average mpg on your rig over a number of years? I know you've traveled all over this country, a number of areas we've also been thru. We've been in a couple of campgrounds together, such as Portal and Bella Terra, just never had the pleasure of meeting you and your wife.

My average is around 10mpg depending on the weather mostly. I'm pretty conservative in my driving. i.e. coming to stop lights, 62mph etc. etc. Your mileage will suffer if you hot rod it, as though you could. :B. We weigh in at 49,000#. Hope this helps...Dennis

Thanks for the comments, I'm just trying to weigh a number of variables.
Dennis, you probably don't carry a calculator with you all the time, but what would you estimate your average mpg on your rig over a number of years? I know you've traveled all over this country, a number of areas we've also been thru. We've been in a couple of campgrounds together, such as Portal and Bella Terra, just never had the pleasure of meeting you and your wife.

^^^ Agree 100% mileage is my least concern

Does fuel mileage in these beasts really matter? Asking for a friend. :B.

Really, you bought the coach, you're going to use it. Budget 8 mpg and hit the road. My opinion is it really doesn't matter what mileage I get as long as I get there. If that is important to you then looking for price per gallon is more important. The Gas Buddy app might become your new BFF. If you pay 5 cents more per gallon and get 2 miles more per gallon than "Fred" then the actual cost of your trip will be more so fuel mileage doesn't matter. The way you drive your rig, the weather, wind etc. will have a dramatic effect on your mileage anyway. I get better mileage through Florida than I do climbing the Rockies to Denver. Best of luck....Dennis

There is always the old adage - "If you have to ask, you can't afford it." I figured someone would say this, so I went ahead and said it first.

To the point, I cannot help you but I am certain someone in here can offer some idea.