C7 Questions

[DeanM2]

I bought a 2007 Cat C7 powered RV last year. Just tried towing my 5000 pound Jeep for the first time, and mileage dropped from 8.5MPG average to 6.5MPG average. Also planning a multi-month trip later this year. So my questions:

1. Is there any value in taking my RV to a Cat dealer to have them scan for codes, and to check that every cylinder is producing power? How much might that cost?
2. There is an oil leak somewhere near the HEUI pump. It has apparently been leaking for quite a while and the oil/dirt is quite thick in that area. It does not leak enough to end up on the ground, just on the engine. Is this something I should worry about?

Thank you for your time.

[gatorcq]

First what speed?
At Camp Freightliner (Mike Cody) stated the sweet spot is 1620 to 1670 RPM.

As for leak, especially near the HEUI, yes, get it check and repair.

Last Oil is (IMO) the most important thing for a CAT.
Per Cat on Oil Change
11,000 miles, 1 year OR 1000 gallons of fuel burned. IMO this is non-negotiable.

[FIRE UP]

Originally Posted by dmevis

I bought a 2007 Cat C7 powered RV last year. Just tried towing my 5000 pound Jeep for the first time, and mileage dropped from 8.5MPG average to 6.5MPG average. Also planning a multi-month trip later this year. So my questions:

1. Is there any value in taking my RV to a Cat dealer to have them scan for codes, and to check that every cylinder is producing power? How much might that cost?
2. There is an oil leak somewhere near the HEUI pump. It has apparently been leaking for quite a while and the oil/dirt is quite thick in that area. It does not leak enough to end up on the ground, just on the engine. Is this something I should worry about?

Thank you for your time.

Well Sir,
First off, if you're actually getting 8.5 mpg on a regular basis, that's darn good in my opinion. Most of us C-7 pilots hover between 6.5 and 7.5 no matter WHAT we're towing or not towing. These rolling gymnasiums are not designed to get wazoo mileage. We've owned our '04 Itasca Horizon 36GD with the CAT C-7 330HP and Allison MH3000 trans now for right at 8 years. We purchased it with 40K on the clock and it now has 91K on it.

That C-7 rarely get's over 7 - 7.2 mpg, period. We tow two different toads. One, a 2015 Jeep JKUR with minor mods, bumpers, tires and wheels etc. And, our second toad is an '11 GMC Sierra 1500 4x4 Extended cab. The truck quite often is loaded with a Rampage lift and, an '08 Honda GL 1800 Goldwing. The truck is right at 5,300 lbs, the Rampage, close to 275 lbs and the Wing, just close to 900 lbs. So, all in all, when the truck and Wing are being dragged behind us, we're toting around 6,700 lbs, plus or minus.

And, with that load, we hover around 6 - 6.5 or so. And often lower, depending on grades encountered. It is what it is. I didn't buy it for gas mileage. As for yours, well, again, if you get 8.5 AT ANY TIME, that's phenomenal in my book. As for your leak, well, if it were me, I'd do whatever it takes to CLEAN that engine thoroughly so that you can ACTUALLY SEE where that oil leak is emanating from. Trying to surmise on a dirty engine is useless. Yeah, cleaning an engine in that kind of engine compartment, bedroom, precious stuff around, kind-a tough to do. But, this way you'll know EXACTLY where it's coming from and, maybe how to remedy it.
Scott

[Dick1142]

My MPG average for the last 70,000 miles, almost all pulling a Honda CRV, is 8.0. This is on trips from one side of the country to the other, both southern and northern routes. Dick

[mrboyer]

We have traveled 109,000+ miles and consistent average per tank of fuel is 6.7mpg towing a Chevrolet Equinox or not towing.

[Airstreamer6]

The mileage one achieves is greatly influence by the speed and other conditions of the trip: the faster and the steeper the traveling, the less the mileage. Of course, there are a lot of other things involved, including the weight and shape of the vehicle and efficiency of the engine.

Sometimes it's hard to compare mileage because of all the variables.

[majicchuck]

Originally Posted by dmevis

I bought a 2007 Cat C7 powered RV last year. Just tried towing my 5000 pound Jeep for the first time, and mileage dropped from 8.5MPG average to 6.5MPG average. Also planning a multi-month trip later this year. So my questions:

1. Is there any value in taking my RV to a Cat dealer to have them scan for codes, and to check that every cylinder is producing power? How much might that cost?
2. There is an oil leak somewhere near the HEUI pump. It has apparently been leaking for quite a while and the oil/dirt is quite thick in that area. It does not leak enough to end up on the ground, just on the engine. Is this something I should worry about?

Thank you for your time.

I think there is value in taking it to a CAT dealer. Cost all depends on the labor time. Not much to scanning for codes. However if you want to check for loss of power that can be a host of things. Last year, I had the Heui and all injectors replaced. I would say get oil leak fixed right away. My leak turned into a much bigger leak. Oil was spewing out of the radiator. Thought it was related to overfill. Had to have gaskets replaced and radiator taken out and cleaned. Engine had to be dropped to install new kit. My scenario was not cheap.

Hope your issue is a simple fix.

[TonyMac]

My C7 gets in the low 8's towing a 4300 pound 2-dr S-10 Blazer with a 28,000 40' DP.