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Robert, RV Mechanic
Category: RV
Satisfied Customers: 13226
Experience:  18 yrs. RV experience including Cummins North West, Country Coach, Monaco Coach - vendor certified.
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Colorado: a class A 38 to 40 foot RV..Diesel..Puller

Customer Question

Which is the better engine to have in a class A 38 to 40 foot RV? I will be going to the 12,000 foot level in Colorado. Diesel Puller? Diesel Pusher? Or gas engine?
Submitted: 6 years ago.
Category: RV
Expert:  Robert replied 6 years ago.

Hi There!!!


Thanks for Choosing Just Answer...


I would say the diesel pusher for that size would do a good job way better then the gas engine, the front diesels are also OK but the rear pushers are more common and easier to work on. The diesel engine will put out more torque for pulling and climbing hills. The most popular are the CAT and Cummins engines for this size and they come in different sizes which equals more horsepower. Hope this helps..


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Customer: replied 6 years ago.
I was told that if I get a Cummins egine that I would need a minimium of 375 HP to go to the 12,000 foot level. I do not know about the Cat engine. Which is the better choice and why?
Expert:  Robert replied 6 years ago.

The higher the engine class the better job it will do. So for the Cummins ISC might be a little lacking as the HP is 330 or 360. The next class is the ISL which would be around 400 hp and then the ISX which is the biggest engine you will find in a RV. CAT also has it's classes the C7, C9 and C-13 each compare to the Cummins classes.


The only reason I would go with Cummins is because CAT has stopped making engines for the RV application, where cummins is going strong, this means better support and better service. Cat makes a great engine and the C9 would probably work for your needs as it is rated around 400 hp.


I am a Cummins guy had the chance to work for them and seen allot of there product, the ISL is a good engine and should do a good job, have never really seen many issues with them. I also got to work on some CAT engines at country coach and they do have the power so my final opinion would be on the fact that cummins is still going strong with the RV application where as CAT is not... Hope this helps...


Customer: replied 6 years ago.
So if I get the Cummins engine are you saying that it should be 400HP Like the Cat?
Expert:  Robert replied 6 years ago.



Each manufacturer has there different class engine, which compare in horsepower. SO the entry level for a cummins in a RV (newer one) would be a ISB for Cat it would be a C-7 these are the entry level. Next you have the ISC for cummins and the C-9 for CAT and then the top engine with the most horsepower is the ISX for the Cummins and the C-13 for the CAT. So in a sense they do compare each class, hope that makes sense... One thing to point out is that each class can be rated for different hp so for example an ISC can be 330 HP or 360 HP depending on what year and what the RV manufacturer build was, so it is important to ask what the HP rating is...




Customer: replied 6 years ago.
So again How much horse power do I need on a cummins engine if it is compareble to the Cat C-9 400hp? Are you saying that each year has a different horse power? So should I eliminate purchase of older models? and only look for the newer Cummins RV's? If so what years (I am not looking to buy new).
Expert:  Robert replied 6 years ago.



The newer electronic engines started around 1998 as years went on they improved. I would say about 2002 and higher would be good if that is what you had in mind. The ISL400 compares to the CAT C-9 400. I would have a full chassis inspection done prior to purchase on which ever you choose. This takes about 2 hours of labor. The interior items can also be inspected and that also takes two hours. I would be looking for someone that has performed maintenance yearly and has had any updates or campaigns done. owners that perform regular maintenance have less problems then those who ignore it. In you case I would go with a Cummins ISL class or higher, cummins also had an ISM engine and that is a workhorse also 500 hp. I know it seems like allot but I would stay away from the ISB and ISC if you are looking for power climbing the mountains...


Customer: replied 6 years ago.
What does it mean to have an update or campaign done? Is this mandatory as with yearly maintenance? Am I the one paying for this 4 hours of inspection prior to purchase and if so how much is considered reasonable for this inspection?
Expert:  Robert replied 6 years ago.



No problem....


Cummins has service campaigns that come out, if you go to an authorized Cummins shop they hook up to the engine computer and can tell what needs to be done, you do not pay for these campaigns or updates. This can be anything from an emissions updates to a fuel line bracket replacement.


Normally a dealer will do a pre-delivery inspection, this will check everything from the chassis to the roof. They have a check list to follow and should replace anything that is not working. A private seller would normally not do this and if you are buying from a private seller it takes about 4 hours labor (100 an hour average) to do the inspection. The shop will report any problems to you so you know what is going on.

The best built RV'S can have problems so it is a good investment to inquire about the inspection or have one done.. Hope this helps..


Customer: replied 6 years ago.

So,this is good to know. So is it better to have all inspections done at the Cummins dealership or just the updates and campaings? Also, is there a Cummins dealership near Lynchburg, Virginia 24550zip?

Expert:  Robert replied 6 years ago.



Cummins has places called Coach Care, these shops are set up for the RV customer, I have worked at one and it was a very organized clean shop with allot of good techs. Any RV shop can do the pre-delivery inspection, any shop that has the Cummins insite software can check for campaigns. I would try if you can bring it to a Coach Care because they are really geared up for working on the RV application. Some dealerships are OK also but it depends on which one. HERE is the map of all the Coach Cares, there is one in VA and NC might be close to you or worth the drive. They have water and power hook ups also meaning you can most likely stay overnight if needed..... Hope this helps..