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Tireabusa

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Apr 20, 2018
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Looking at used Class A diesel pushers. The most popular engines are the Cummins variants, but I see Mercedes, Maxxforce, etc. Obviously big diesels have a reputation for longevity, but has anyone actually had a blow up on one of these motors, and if so, at what mileage ? Regarding the Cummins, are there more of them out there because Cummins sell them to RV manufacturers at a cheaper cost ? We all know Mercedes are very " price proud" when it comes to their products.

I see used RV's with 50,000 to 90,000 miles on them, ...........are there any repeat problems with turbo's at certain mileages ?
 
This seems to be a huge worry on this board but I have to be honest - I don't get it.  RV's very rarely get enough mileage to blow a motor and the companies that make them kinda know what they are doing.  I have a Cat in mine and the last thing I was worried about when I bought the RV was the motor.

I mean anything could blow if it was run out of oil but other than that type of abuse they should be good for the life of the RV.  Then if you wanted you should be able to pull them out and put them in something else.

I know someone on here says their motor went but there was a whole novel that went along with that story.

Chill out and chive on!
 
DPs in more recent years will pretty much all use Cummins, since no one else is making diesel engines large enough -- CAT quit making them for RVs a number of years ago. All the Mercedes that I've seen are the 3 cyl. units for the Sprinter chassis, which is a rather small RV. But the CAT and Cummins engines are all good units, though I seem to recall someone mentioning something about a specific Cummins unit needing special care. I've had both brands and they do well.
 
Mercedes have a 7.2L diesel for RV's..............I have seen it in a Forest River. I know the motor in the Sprinter but thats not what I mean.

KandT, regarding being worried about the engine, it seems quite normal when you are new to buying a used RV to know if turbo seals go at a certain mileage so you can deal with it before it happens.  Did you buy your 2005 model from new ??
 
I have a cummins in mine. I own four pieces of heavy equipment. Two are cat. All I can say about Cat is, if you need any parts, they seem to think they are gold plated when it comes to prices for their parts.
 
KandT said:
This seems to be a huge worry on this board but I have to be honest - I don't get it.  RV's very rarely get enough mileage to blow a motor and the companies that make them kinda know what they are doing.  I have a Cat in mine and the last thing I was worried about when I bought the RV was the motor.
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Many (most?) of us grew up in an era when gasoline car engines were good for ~100,000 mile, but even that metric is way low for today's engines.  Large block diesels have always been built for longer service so using a "car engine mentality" when evaluating diesels leads to all sorts of false assumptions.

My 12-liter CAT now has 109k miles on it; it had 55k when we bought it.  I can honestly say it seems to run smoother now than it did when we first bought it.  I'm not too worried about maintaining it.  Except for routine oil and filter changes I think the next "major" service is a valve adjustment at ~250k miles.  I may or may not live to ever see that.  It's my understanding that heavy duty CAT and Cummins engines (the larger ones ~>9 liters) are all have design philosophies of "first in-frame rebuild at ~750k miles" so wearing them out isn't all that much of a concern.

Prior to CAT exiting on-highway truck engines in ~2008, CAT and Cummins shared most of the Class A DP market.  Navistar engines were used during the couple of years when Navistar owned Monaco.  I don't think Mercedes engines have ever been used in larger mass market MH's  here. 

There are still thousands of heavy trucks with CAT engines rolling around the US so I'm not the least bit concerned about service and parts.
 
Mercedes no longer has a medium size, US-certified diesel. They had one for 2007-2008 but apparently it didn't pass muster for later EPA standards. Since Daimler-Benz  also owns Detroit Diesel, which has a full line of medium & heavy diesels for the US market, they apparently decided not to sell an M-B branded truck diesel here. Just the smaller Sprinter and car-size diesels.

Agree with the others - engine brand is not worth worrying about, or even preference.  Cummins are excellent and the service and parts network also quite good, but Cats are easy to get fixed as well.  Besides, much of what people thing of as "engine problems" are not the engine manufacturer's bailiwick at all, e.g. cooling system, fuel system, air intake & exhaust, etc. Those are all supplied by the chassis builder, not direct from Cummins, Cat, MB or Detroit.
 
Tireabusa said:
Mercedes have a 7.2L diesel for RV's..............I have seen it in a Forest River. I know the motor in the Sprinter but thats not what I mean.

KandT, regarding being worried about the engine, it seems quite normal when you are new to buying a used RV to know if turbo seals go at a certain mileage so you can deal with it before it happens.  Did you buy your 2005 model from new ??
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Nope - bought it from the original owner.  If the seals go (it has 20K miles now) I will deal with it then.  There are lots of things that might happen.  I don't have time to worry about them all! ;) ;)

Now - old tires or steering or brake issues get addressed ASAP or before!!
 
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