Diesel Pusher questions... 5.9 or 8.3?

[surfbeetle]

My wife and I are thinking we'd like to get rid of the fifth wheel and get a diesel pusher. Maybe an older one, late 90's or early 2000's. I used to drive school buses so driving the RV isn't an issue. I don't like the Cat diesels, they were always gutless. I liked the Cummins 8.3 but I never had to work on them. On RVtrader, there are several 5.9s and 8.3s. How are the 8.3s compared to the 5.9s? In my perfect world I'd like a p7100 pumped 12 valve. Thanks

 

[JR]

I can tell you we've got 3 of them at work, ranging from about 9800 hours up to 19k+. Two are in cranes and one in a track mobile, the track mobile (the one with 19k hours) gets the dog snot run out of it 24/7/365 by a bunch of uneducated operators. None of the engines have required anything other than routine maintenance.

 

[Bob4x4]

Go with the 8.3,the 5.9 is just not that nice for that much weight and the big sail of a front end

 

[Bob V]

I know where there is a nice 5.9 powered in Oregon if you are interested PM me

 

[TFucili]

Go with the 8.3,the 5.9 is just not that nice for that much weight and the big sail of a front end

+1, Get the bigger hammer.

 

[mwilson]

I have to agree. I don't recall anyone ever coming into our dealership and requesting less power...

 

[MMeier]

Yep, what they said! Bigger is definitely better in this case .

 

[Joseph Donnelly]

If you get one with the VP44, read the threads on problems with it. You probably shouldn't add a power box to the 8.3, the pump can't take it well according to TST.

 

[mwilson]

The VP-44 in a commercial chassis has the benefit of an available software / kit update that puts the Check Engine light on if the lift pump fails before it has a chance to smoke the VP-44.

Never admitted that there was a problem, mind you but came out with that after VP-44's were being constantly changed under warranty as a result of failed lift pumps.

Mike.

 

[p-Bar]

My understanding Cats were short lived in the motorhomes

 

[Shadrach]

The 8.3 engines before 98, just like the 5.9 had the Bosch P7100 fuel pump. It is a good engine as well and a bite more suited for a larger vehicle. David

 

[johnrv4]

I'd definitely go with the 8.3. I had a '98 Newmar with a 325 HP p-pumped 8.3. That machine really ran great and the fuel mileage wasn't bad. The problem for me was all the other costs associated with a big rig. Big $$$ tires, radiator, and other related costs. There's a lot of systems on these rigs, and even the engine parts are more expensive when you get bigger than a 5.9.

 

[mwilson]

John makes a good point in regards to it being truck components when you jump into that category of motor home.

But I would not be afraid as I am used to this stuff. As with anything you must ask yourself if you can handle some repairs on your own. Most shops have a different labor rate for these as it is harder to get to anything on the engine.

I would have these items at the top of my shopping list....

(1) No CATS. Cummins only.
(2) Air Brakes. Would not give a second look at one equipped with hydraulic brakes.
(3) Can the radiator and / or the charge air cooler be removed easily? If you start looking you will see many equipped with a one piece rear end cap. You can't get the radiator out easily, if at all.The better ones have a two piece rear end cap so the lower half can be removed.
(4) Fan drive. How does it work? If you see that the cooling fan is hydraulic drive walk away. Extremely expensive to fix and usually drive from a pto / pump unit mounted on TOP of the Allison. Not a good time for owner or technician.
(5) Does the bed flip up to allow access to the engine from topside. Do the slides have to be put out to get the bed flipped up?
(6) Tire. I would be looking for 22.5 low profile. The cheapest to buy. 19.5 are not too bad either, but usually see that size on the smaller motor homes.
(7) Check the batteries and cables, look close as there may be a second set elsewhere. Any green goo, crud on the batteries, evidence of several electrical repair attempts? Walk away.
(8) Look for a diesel genset in the nose. If equipped can it be slid out for easier service? Many have this feature.

Just a few thoughts from some the worst that we have had in the shop.....

Mike.

 

[zb39]

8.3 for sure. When I went from gas to DP I went straight to the 8.3. It was 2003 and I bought a 2000 Damon Escaper on a Sparten chassis with ISC. Had it for 6.5 years, 40000 miles, never a problem. Drove it to Alaska and back, among others. Sold it and bought a Tiffin Zephyr with the ISM, 10.8L and a tag. 45 feet. Just sold it a few months ago. The first time in 22 years I don't own a coach.

 

[surfbeetle]

Lot's of great info here from you all. Thank you so much. Unfortunately, my situation has changed and I will mostly likely have to wait 6 months to a year before I can make the purchase but all of this info definitely allows me to make a better decision.

 

[Shadrach]

With a lot of the "smaller" motorhomes ( usually with a 5.9 ) when you open up the engine bay door at the rear all you see is rad. When you get into the bigger units, and this includes the 8.3 powered ones, you can see the engine from the back and the rad and CAC are mounted on the left side of the coach. It is a lot easier to work on this style. MH are famous for "rusty" engines because the engine bay is tight and hard to get in to clean so they don't get washed as often and also retain a lot of heat. I have sold many exhaust manifolds and lots of mounting bolts because of broken ones.

Bottom line -You have to not only be able to afford to buy a MH but also be able to afford to maintain and repair it.

David

 

[CToney]

No experience with 8.3s in motor homes but we have them in our tractors and combines on the farm. The 8.3 is a good engine but not as bulletproof as the 5.9. Our 230 hp 8.3 popped a head bolt, our 215 hp 8.3 in a combine ( it revved 2750rpm for 2600hrs before it dropped a valve). A friend of mine has also had to do head gaskets on his 8.3s. In my opinion a 5.9 can handle more abuse and its a bit cheaper and easier to fix. Don't get me wrong I still think a 8.3 is a good engine but it can't handle being rode hard and put away wet like a 5.9 can.