[jimmitchell4570]

My 6.7 8.9 liter Cummins Diesel engine installed in a 2009 Tiffin Motorhome must be a an indication that this engine is a very weak engine. After 85K miles two Cummins shops checked it and said that it has excessive blowback and needs an overhauled. Another owner that I met at the Cummins shop in Ogden, UT who also owned a 2009 Tiffin MH with a Cummins engine had the same problem and his overhauled it at 70K miles and again at 95K miles. Cummins may be guilty of false advertising when they advertise that their diesel engines are good to 200K to 500K miles.
Any suggestions?

 

[Cartwheels]

Yes these are definitely very light duty engines, very few make it past 100k before needing overhauled, I think @gsbrockman may have more insight and pictures he could put up here to help with my point.

If the reason for needing overhauled is because of blowby concerns I'd guess someone is idling a lot or else running with no air filter.

 

[5.7 Hemi]

Tell that to the hotshot guys.

 

[Loki223]

My 12 had 200k when i sold it, current 18 has just shy of 80k, my buddies 11 is currently around 240k i think. The issue isn't with the motor, but something else that's causing it to have premature failures. These engines are widely considered barely broken in at 200k

 

[mattswaggs]

What were your oil change intervals?

 

[David Ivory]

My 6.7 liter Cummins Diesel engine installed in a 2009 Tiffin Motorhome must be a an indication that this engine is a very weak engine. After 85K miles two Cummins shops checked it and said that it has excessive blowback and needs an overhauled. Another owner that I met at the Cummins shop in Ogden, UT who also owned a 2009 Tiffin MH with a 6.7 liter Cummins engine had the same problem and his overhauled it at 70K miles and again at 95K miles. Cummins may be guilty of false advertising when they advertise that their diesel engines are good to 200K to 500K miles.
Any suggestions?

I have seen several 16,17,18's with over 300K on them. No problems at all. In my opinion because the newer trucks are so complicated, if there is any major failure then time to get rid of it. Between the emissions BS and the automatics even dealerships have a hard time correctly making repairs.
All my trucks are first gens. They don't have lots of power, not designed very well and have some quality issues but they are simple and easier to repair.
Friend of mine was a RAM product specialist for many years. He knows EVERYTHING about every year diesel. He has a 2017 3500 that he likes. He also mentioned he really like the 2003 and 2004's with the manual trans. Said those were "really good trucks"

 

[xcc_rider]

Googled 2009 Tiffin MH weight and got 26k unloaded.
Add 2-3k for packed with water full and you've got a 6.7 cummins pushing over 28k day in and day out.
Add that most owners don't warm the engine up prior to hitting the highway and you've got an engine that's working very hard it's whole life.

Service intervals from air cleaner and oil are critical under that kind of load.
As is excessive idling (not using the high idle feature).

I think that a 2009 ISC 6.7 (360hp/1050 ft# torque) is still working hard for that kind of service and 80-100k is all I'd expect under those conditions, given most owners really don't know how to take care of a diesel to increase its longevity.

I've only got 119k on mine (in 15 years) towing 8500 # and I expect I'll be worm food before it needs rebuilt.

 

[mattswaggs]

Googled 2009 Tiffin MH weight and got 26k unloaded.
Add 2-3k for packed with water full and you've got a 6.7 cummins pushing over 28k day in and day out.
Add that most owners don't warm the engine up prior to hitting the highway and you've got an engine that's working very hard it's whole life.

Service intervals from air cleaner and oil are critical under that kind of load.
As is excessive idling (not using the high idle feature).

I think that a 2009 ISC 6.7 (360hp/1050 ft# torque) is still working hard for that kind of service and 80-100k is all I'd expect under those conditions, given most owners really don't know how to take care of a diesel to increase its longevity.

I've only got 119k on mine (in 15 years) towing 8500 # and I expect I'll be worm food before it needs rebuilt.

I don’t think that’s it, I think it’s lack of maintenance.

 

[Cartwheels]

Googled 2009 Tiffin MH weight and got 26k unloaded.
Add 2-3k for packed with water full and you've got a 6.7 cummins pushing over 28k day in and day out.
Add that most owners don't warm the engine up prior to hitting the highway and you've got an engine that's working very hard it's whole life.

Service intervals from air cleaner and oil are critical under that kind of load.
As is excessive idling (not using the high idle feature).

I think that a 2009 ISC 6.7 (360hp/1050 ft# torque) is still working hard for that kind of service and 80-100k is all I'd expect under those conditions, given most owners really don't know how to take care of a diesel to increase its longevity.

I've only got 119k on mine (in 15 years) towing 8500 # and I expect I'll be worm food before it needs rebuilt.

Its very likely the engines are derated similar to the CC pickups and my understanding is the reason for the derate is because they are expecting them to be worked hard and put away wet every day of there life.

 

[Lins]

I don’t think that’s it, I think it’s lack of maintenance.

Bingo

 

[Max Tune]

Id say it's a guy that joined 13 hours ago, made one post at the beehive, then left.....

 

[David Ivory]

I don’t think that’s it, I think it’s lack of maintenance.

 

[Scott_Cummins_Newbe]

People forget just how many applications the 6.7 is used in. From non-commercial Trucks, motor homes, millions of school busses and delivery trucks. It is historically a very good diesel engine if not the best in its displacement. How the engine is married to a particular platform, how it is operated and maintained has more to do with the longevity of the engine than anything else. Any engine can get killed pre-maturely when used or maintained improperly.

 

[mattswaggs]

Cummins failure in this particular application is they didn’t make the blinky light that said to change the oil blinky enough.

I always change oil at 5k miles. Maybe that’s too often, but I’ll live..

 

[jimmitchell4570]

I really appreciate your quick responses. I am sorry but I didn't give the correct model for the Cummins engine. It is an 8,9 Liter and i think is an ISL. We have not been close to the MH for over a year because the health care suppport is much better here in Cincinnati than in New Mexico.. However, would your comments be the same? I purchasaed the MH from an individual with around 55K miles on it and it looked like he took very good care of it. I think the recommended oil change schedule was 15K miles but I changed it more often than that.

 

[mattswaggs]

@Loki223

I was thinking this was spam yesterday. Now I’m certain.

 

[cumminsturbofreak]

@jimmitchell4570

I just had to delete 17 posts that were all the same. If you spam post like that again, you will get an official warning.

You only need to make one or two response posts, NOT 20.

 

[jimmitchell4570]

@jimmitchell4570

I just had to delete 17 posts that were all the same. If you spam post like that again, you will get an official warning.

You only need to make one or two response posts, NOT 20.

Sorry about that. I was only trying to respond to everyone that had responded to me. jhm

 

[cumminsturbofreak]

Sorry about that. I was only trying to respond to everyone that had responded to me. jhm

Yep I figured.

Just remember, this is a forum. Unlike Facebook or Reddit, a reply will be seen by everyone in the thread. So if you have a general reply, you can post one and we will all see it.

 

[fatman45]

I purchasaed the MH from an individual with around 55K miles on it and it looked like he took very good care of it. I think the recommended oil change schedule was 15K miles but I changed it more often than that.

Looked like he took good care of it? I once bought a 1986 S10 Blazer with 85K on it. The guy swore up and down that it was "well maintained". I went over everything as is my custom when purchasing a used vehicle. The distributor cap and plug wires were the factory originals. I concluded his idea of "well maintained" meant that he put gas in it every time it ran out.

It sounds to me like the guy you bought from rarely, if ever, changed the oil. I have a 2006 3500 with the 5.9L, 300K and running strong. I change the oil every 5K. The manufacturer recommends a longer interval than that, but we have different goals in mind. They would like to sell me a new one every couple of years, whereas I would like it to go 1 million miles before I need a new one.