Cummins Diesel Engines--Reliable???

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gary41

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Been reading comments like "make sure it's an "ISC, NOT an ISB" Cummins..but have not seen any data on the reasons for that statement.
I know the ISB is the smaller engine.? ?I have also seen a couple of ads where it's stated that a new Cummins was installled 8 to 10K miles ago!
(in motorhomes that had less than 50K miles)? Maybe it's a case of ignoring oil and filter changes..?? Does anyone know the real story on Cummins?
 

gary41

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Huntsville, AL
Hi, Smokey!....We are considering a 1999 Discovery 34 M34-Q with the 275 Cummins.. Has only 10K miles for $62,900.  Seems like a good deal :-\
Any comments would be most welcome!
 

rhmahoney

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The key point is the 275 Cummins. That is probably the ISB and is likely to be grossly underpowered.
Always look for 100 lb GCVW/1 HP. This gets important out here in the mountainous west.
 

blueblood

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gary41 said:
Hi, Smokey!....We are considering a 1999 Discovery 34 M34-Q with the 275 Cummins.. Has only 10K miles for $62,900.? Seems like a good deal :-\
Any comments would be most welcome!

First, in spirit of full disclosure I am a former VP of Cummins and therefore not unbiased.  But second, I am the owner of a  99 36T Discovery with 80,000 miles and had minimal problems and I know literally 100's of others who have same experience. In fact, one of my close friends just traded his 99 with over 120,000 trouble free miles. There was one episode around 2000 where several engines were built with faulty cast blocks but in the Discovery Owners Association Inc. membership of nearly 1500, the experience has been very good. Go to  http://www.discoveryowners.com/forum/default.asp and ask your question on this bulletin board and see what answers you get. (Remember that Fleetwood changed all products to CAT in later years)  Fuel economy has been excellent averaging around 10 -11 MPG. As to underpower, it certainly will not run at 75 mph up a major 6% grade. However, I lived until this March in UT at 7000 ft and thus had to travel the mountainous west routinely pulling a toad (including getting to my home up the climb out of SLC to Parley's Summit on I-80) and the performance was good i.e. probably do most major climbs at 40-45 mph. We have members who pull large trailers with cars including one who has a Corvette inside and they go everywhere with no apparent problems. The excellent fuel economy is a good trade off to a much higher HP engine like ISC for a vehicle this size. If you do buy seriously consider joining the DOAI and Discovery International (FMCA). PM me at [email protected] if you have any other questions or would like to discuss further.
 

BernieD

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gary41 said:
Been reading comments like "make sure it's an "ISC, NOT an ISB" Cummins..but have not seen any data on the reasons for that statement.
I know the ISB is the smaller engine. 

Gary

The reason for the differentiation between the "B" and "C" engines is strictly a matter of hp and torque. Yes, the 5.9 liter "B" engine is smaller, up to 300hp and 560 ft-lbs of torque. The 8.3 liter "C" has up to 350 hp and 1050 ft-lbs. Quite a difference. The 5.9 engine is a strong engine in Dodge pickups, not so strong in 25k# motor homes.

 

dsl4us

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gary41 said:
...We are considering a 1999 Discovery 34 M34-Q with the 275 Cummins.. Has only 10K miles for $62,900.?

With only 10K it isn't even fully broken in. We'd really like to have that 275hp in our motor home, currently have the 190HP 5.9L Cummins. It also has 139,000 miles on it. Only major part it needed was an injection pump.

The owners manual for ours stated the engine was warrantied for 300K, forget time frame. That unit should pull circles around your current gasser.

The bad block issue is well know over at the TDR, a Dodge/Cummins enthusiast website. The potential bad blocks have a "53" cast into them. Not all bad or leak right away. One members engine started leaking with 220K on it, currently my '53' block has 173K on it with no leaks.

What transmission does that unit have?
 

Jim Dick

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gary41 said:
Hi, Smokey!....We are considering a 1999 Discovery 34 M34-Q with the 275 Cummins.. Has only 10K miles for $62,900.  Seems like a good deal :-\
Any comments would be most welcome!

Hi Gary,

As someone mentioned, that engine isn't close to being broken in yet. I've owned 3 coaches with cummins diesels, a 230hp B, a 325hp mechanical C, and now a 350hp ISC. All of them have been great engines. My current ISC now has about 69,000 miles on it with no problems whatsoever. I would not hesitate to buy another if a coach I liked had one.

As Russ mentioned, the key is the GVWR vs. HP. A 30,000lb coach should have at least 300hp for adequate performance. However, coaches with less will still get you down the highway, just not as fast on the mountains.
 

blueblood

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gary41 said:
Hi, Smokey!....We are considering a 1999 Discovery 34 M34-Q with the 275 Cummins.. Has only 10K miles for $62,900.? Seems like a good deal :-\
Any comments would be most welcome!

I would like to add a further comment. You note that motorhome has only 10,000 miles in roughly 7 yrs. This can be good from one perspective but problematic from another. The concern for me would be understanding the owners driving pattern. If they drove it on relatively short trips spanning the years it would not be as much concern as if they drove a few long trips and left it sit for extended times. The latter because of potential seal dry out on all movong parts including engine, tranny and chassis.  I would look carefully for signs of oil leaks from gaskets around valve covers. oil pan, air compressor, wheel bearings,etc. Look for any sign of oil seeping from large  hole at bottom of flywheel housing which would indicate a main bearing seal leak. I would then drive it a considerable ways and check them all again. This will NOT assure they won't leak in near future after some hard drivng but would at least catch them if problems are apparent now.
 

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