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imjustdave 05-07-2021 09:12 AM


Originally Posted by Chargersrt8 (Post 5741503)
He posted that the engine and trans is for sale and the rig is at his permanent site for life. Engine is dead, he is alive.

Post #22 is not the same person as post #1

See post #25 as well

OP hasn't been back sense post #1 :banghead:
Last Activity: 04-22-2021 10:59 AM

dmarrs8585 05-07-2021 10:13 AM


Originally Posted by Arch Hoagland (Post 5741318)
Remove and repair.

So what's remove and replace?

Xmcdog 05-07-2021 10:25 AM


Originally Posted by Arch Hoagland (Post 5741318)
Remove and repair.

Remove and replace? Just asking.

wolfe10 05-07-2021 10:47 AM

R & R means REMOVE and REPLACE.

Can replace with same part, rebuilt part, new part, etc. This based on 35 years in the automotive field. Doesn't mean someone can't invent their own definition!

Arch Hoagland 05-07-2021 11:09 AM

R & R Remove and repair,,,,I'm an optimist

Dan50 05-07-2021 11:17 AM


Originally Posted by Arch Hoagland (Post 5741318)
Remove and repair.

Remove and replace.

Rorytug 05-07-2021 02:42 PM

The governor is a likely suspect.

Originally Posted by wolfe10 (Post 5724014)
Would like to hear more on the root cause of the run away (excessive RPM).

Was this on start up (in neutral)?

While in gear?

Excessive oil leakage from turbo into intake side (would need to be pretty massive)?

Throttle stuck?


As a young man, I was a Fleet mechanic a bus company. Mostly Detroit Diesels. The number one cause of runaway back then (1980) was a worn governor. The first sign of a worn governor is surging at idle that can't be smoothed out with adjustment. Had a couple run away while trying to adjust the idle. 95% of our busses were manual transmissions so if you were fast enough, you could jump in, get it in 4th gear and dump the clutch wile sanding on the brakes.... That was always fun. I saw only one run away so bad we all ran for our lives and pistons and pieces parts flew everywhere like shrapnel!:eek:

In the 4 years I was there, we never had one runaway in the field, always in the shop. Some busses had petcocks in the fuel line so you could turn off the flow but it is surprising how much fuel is in those lines and how long it takes to suck dry.

Ljwt330 05-07-2021 02:53 PM


Originally Posted by wolfe10 (Post 5741834)
R & R means REMOVE and REPLACE.

Can replace with same part, rebuilt part, new part, etc. This based on 35 years in the automotive field. Doesn't mean someone can't invent their own definition!


Originally Posted by Arch Hoagland (Post 5741859)
R & R Remove and repair,,,,I'm an optimist

LOL, I love this!

It's all from one's perspective. If you're a DIYer, it means REMOVE AND REPAIR. If you're a lazy or marginally qualified DIYer, it may never get REPLACED.:eek:

If you're a pro, it means REMOVE AND REPLACE, otherwise you don't get paid.:D

tinman 55 05-07-2021 10:35 PM


Originally Posted by AnotherMike (Post 5741398)
I do two-way radio and some computer networking, so I have very little hands-on experience with diesels. But I can answer your question...
The one diesel I worked on used a solenoid driven shutoff valve in the line between the engine and the fuel source... either the tank or the fuel pump.

In a gas engine you shut it off by turning off the ignition. Diesel engines do not have an ignition system. The only way to shut off a diesel engine is to shut off the air or the fuel.

Now take the situation of a blown oil seal in the turbo... where the leaky seal allows lube oil to be pumped into the air intake of the engine... and acting as diesel fuel. The engine will run until there is no lube oil. The engine speed will depend on the feed rate of the lube oil. No ECM involved in this "fuel" supply.

Likewise a "dusted" engine... where the dirty / dusty air it has inhaled has gotten past the air filter and scored the cylinder walls, and the lube oil is getting past the piston rings... This is again acting as diesel fuel. If the amount of lube oil getting past the rings (frequently called "blowby") is enough then it will continue to run until there is no more lube oil. Again, no ECM involved in this "fuel" supply.

In either case the closure of the fuel cutoff solenoid valve will have no effect. At that point the only way to the engine down is to cut off the air intake. Back in the 1970s I watched a mechanic in a diesel shop lay a phone book across the turbo intake (the air cleaner was not on the engine) of a bulldozer engine, and a few years later saw a truck driver take his jacket off and zip it up across the air cleaner intake...

Generally speaking, the intake air flow from somewhere outside of the MH to the air inlet of the turbo (or engine) almost always has to make a few turns to fit into the engine compartment. That run always contains an air filter assembly somewhere. Each turn usually involves a rubber sleeve & large clamps (of some kind) to connect to the next piece of air pipe or air duct. Plus there will be another flex sleeve to connect to the turbo. A damaged air filter, a crack in the filter box, a hole in any of the air tubes, or a tear or hole in one of these connecting sleeves can result in dirty/dusty air being sucked into the engine. And any one of those air leaks could prevent the jacket or other plug from starving the engine of air.

You might want to read these threads:
https: //

https: //
That second one is very long (51 pages!), but VERY educational (and a good read, "piker" is a good writer).


Thank you Mike for the response. I will check the links you provided but, the explanation you gave definitely cleared it up.

berkleyja 05-08-2021 07:25 AM

For MobyDick,

Shop around for the 3126B. I have replaced two engines and both were around $25000. The last engine was from a company that rebuilds engines and the engine cost about $15500 and Freightliner in Billings, MT replaced it. My coach is a 2002 Dutch Star on a Freightliner Chassis.

96 Wideglide 05-08-2021 10:25 AM

Re & Re usually means remove and replace.

augerdogger 05-08-2021 11:15 AM

Look at your investment and determine if it more cost effective to repair or part out. I would look for a used engine, most come out of OTR trucks and have been maintained with at least a 90 day warranty, you might find one out of an RV.

Keith55 05-08-2021 12:20 PM

I think Moby is busy selling his engine as "rebuilt" on craigslist.


Dutchstar53 05-08-2021 09:38 PM


Originally Posted by Piros1 (Post 5741369)
First I read all the post, it would suck to be in this position. Sorry for the OP and I surely hope he is getting is situation resolved in a reasonable manor.

I wonder his rig is and what engine? I seen where some posted it was a 3126 Cat. If that is what he has a really doubt it truly was a runaway unless he over ran it down a very steep grade and just over reved the engine. I own several of these in heavier trucks than most coaches with this engine and some approached 23,000 hours of run time, (thatís equivalent to approximately 1,000,000 miles) way more than we see on a Motorhome and have never seen one runaway or over rev do to a worn turbo. That was a common problem on the old Detroit two strokes but not so much on the newer engines from Cummins and Cat. Detroitís were supper charged and they had an emergency air shut off flap you could pull if it it started to run away. You donít get that with a turbo, maybe I should say not impossible but very very rare.

Hopefully the OP comes back and fills us in. Iím sure he is pretty bummed out. I wish him the best.

We have a 2002 Newmar Dutchstar. It came with the 3126B. From the start it had blowby issues. Took it to CAT & it was just within limits. Husband put various catch cans on during the years. It kept getting worse. Tow car would be covered in oil. After 175,000 miles we decided to do a new engine. Got a long block, replaced the turbo, new injectors. $35K. We were told 200k miles was limit. These engines were used in buses, dump truck not heavy haulers. Weíve 50K on new one and so far no issues.

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