Consensus on best diesel engine?

[Wbonsell]

We are contemplating upgrading to a DP...probably in the 98-03 range. Liking Foretravel, American Eagle, Dynasty, etc. Is there a consensus on the best diesel engine. Pretty sure we want a side radiator unit. 36-40 footer. A 36' single slide Foretravel would be my #1 choice.

[Jim2]

In that age range, the previous care & use of the engine will be much more important than the brand name on it.
There are very few or no folks who have used 3 different diesel engine brands over a time period long enough to do comparative analysis. So, the "best" is a purely limited personal opinion. My opinion is that they are all good, your chances of getting a lemon are equal with any brand name, and your best way to minimize future engine issues is to assure that you and the previous owner religiously perform all recommended routine maintenance items.

[FormerBoater]

In almost 7 years of operation and 40K miles, my trusty mechanical C8.3 engine has been 100% trouble free.

Won't say that it is the best, but it is very very good!

[super_rep]

I've had Cummins, CAT, and now a Detroit. All three are great, if properly taken care of. Overall, if I had to make a choice, I think I'd choose my current Detroit as my favorite. But then again, both the two Cummins I've had were good and never really had any problems. The CAT did like to burn a little oil.

You have to look real hard at the maintenance records when choosing one as old as you're talking about. All three brands are good!

[barmcd]

I'm doing the same exercise and think I want a Cummins 8.3 or 8.9 L, mainly because I want a side radiator.

[mhbell]

What would be the reason for choosing a side radiator over a rear one on a DP is one better than the other? I don't have a DP but am curious.
Mel

[Steve Ownby]

Originally Posted by Wbonsell

We are contemplating upgrading to a DP...probably in the 98-03 range. Liking Foretravel, American Eagle, Dynasty, etc. Is there a consensus on the best diesel engine. Pretty sure we want a side radiator unit. 36-40 footer. A 36' single slide Foretravel would be my #1 choice.

Can't speak to best and on this age range, prior maintenance means everything. I know Monaco's very well and consider the Dynasty to be an excellent value in terms of "bang for the buck". In '03 even the short coaches had a tag axle.

http://www.monacocoach.com//library/...03_Dynasty.pdf




Steve Ownby
Full time since '07

[Mr_D]

I'd have to nominate the '07 EPA version of the ISX 650 as the worst! Ours dropped a valve in #6 at 14,000 miles, and again at 45,000 miles and is on it's third turbo. First one was under warranty, second one was not and they are expensive to repair too.

Before that we had the CAT 3126 and other than a lack of torque (for my wants anyway) was a good engine.
Then we had an ISC 350 and it was good too.

[Gordon Dewald]

It all has to do with personal experience. Everyone will form some kind of opinion from that. There are a few engines that have not performed well but overall most are good. Maintenance is key.

[dennis45]

Originally Posted by Jim2

In that age range, the previous care & use of the engine will be much more important than the brand name on it.
There are very few or no folks who have used 3 different diesel engine brands over a time period long enough to do comparative analysis. So, the "best" is a purely limited personal opinion. My opinion is that they are all good, your chances of getting a lemon are equal with any brand name, and your best way to minimize future engine issues is to assure that you and the previous owner religiously perform all recommended routine maintenance items.

X2,

[Jim_HiTek]

Originally Posted by mhbell

What would be the reason for choosing a side radiator over a rear one on a DP is one better than the other? I don't have a DP but am curious.
Mel

A side rad is preferred by some owners because it's easier to work on or service their own engine without the rad in the way. This side rad construction is by necessity, more complex, with hydraulic fans and pressurized hoses steering hydraulic fluid to power the fans. Also, many complain of the cloud of dust the side fans create as you leave the freeway and enter a campground so there's a DIY method to fix that. Doubtful any manufacturer will ever do it.

A rear rad is acceptable to those who don't do a lot of work on their own rigs. Older diesel engines use to have a slobber tube where engine oil and some exhaust was blown out, this would mix with road dirt and grime and coat the rear rad. So it would need to be clean regularly. Others, like me, just put in one less quart of oil during a change. No blown out oil. Haven't had to clean the rad for years now. It is right there in the way though so sometimes I (or a shop) have to access the engine from under the bed. I got a quote once on rodding the rad and the shop told me 1 hour remove, 1 hour replace, so just 2 hours extra if your engine needed that kind of extensive work requiring the rad be removed. Unlikely.

So, your choice is potentially either assume the problems associated with a rear rad or those with a side rad. Neither is perfect. I would NOT base my purchase on where the rad was positioned alone. It's not all that important.

[LDMcL]

I think the Detroit Diesel 6V92 and 8V92 series make the best music, or were you asking about other criteria?

[barmcd]

Originally Posted by mhbell

What would be the reason for choosing a side radiator over a rear one on a DP is one better than the other? I don't have a DP but am curious.
Mel

There are a few, number one is cooling capacity. HP and torque generate heat that has to be dissipated and a side radiator is more efficient than a rear radiator. I've heard that 350 hp is about the limit for a rear radiator coach and that's pretty much been my experience. I haven't seen a 400 hp rear radiator motor home and I've seen 315 hp and up with a side radiator.

The second reason is ease of maintenance. I'll do most of the work myself and I think I can do most anything that doesn't involve rebuilding the engine. A side radiator makes getting to the engine a lot easier. It's also cheaper if you have someone else do it because you don't have to remove the radiator for everything.

The third reason is maintaining cooling efficiency. A side radiator isn't as prone to picking up dirt an debris which blocks the fins. It's also easier to clean.

A side radiator does add complexity and another source of potential failure, but for me the benefits outweigh the disadvantages.

YMMV.

[ecurb74]

The Cummins ISM (M11) is hard to beat. Plenty of HP and torque, especially in a 36 ft motorhome. Couple that with the Allison HD4060 transmission with retarder and you don't have to worry about towing or hills. Nothing like horsepower! Like most other engines take care of them and they will out last you.


Bruce & Teresa
2000 Foretravel U320 4010
Cummins ISM 450hp
Allison HD4060R 6 Spd W/Retarder