And yes, I do know diesel engines can run away on engine oil, but the abuse or neglect of the engine in those cases had to have given signs that something bad was going to happen sooner rather than later well in advance of the engine running away on crank case vapors. Sure, if the engine goes wide open you can shut off the fuel to stop it. But from my experiences, a runaway is not just running wide open like you mash the pedal all the way to the floor. It is way much more wide open than that when a Mercedes diesel runs away. A 603 governed will run 150 mph. So just think what one will run when it is out of control and the sound at 150 mph would sound like the car is coasting as opposed to what it sounds like when it is in RUNAWAY mode. And if my car had hit that oak tree when it ran away on me; it probably would have bounced off of that tree and kept going and destroying everything in its path. I shutter to even think about it being in gear when it took off. Plus, it caught me by surprise and I didn't know whether to run for cover or try to shut it down, which I eventually shut it down by just pulling loose that plastic line, but it still ran a long time before it shut down. The third runaway on a 617, I just let it run to see what it would do when it blew up and it threw the rods out the side of the block and broke up all of that brittle cast iron the engine is made out of. From my experiences, the engine always let me know when it is going to take off. It revs extremely fast when it first hits on start up and it might shut off if I turn the key off quickly and if I turn that key again after the warning the car gives me, it just goes in full blown RUNAWAY mode. But now I am a RUNAWAY expert and make the car runaway on purpose because I now know that if I kill the air supply, it will shut down. That is the only way to become expert on these cars, know how to shut it down and know how to make it runaway. But I will never forget the first and second and third and maybe the fourth times I had run aways. It's something you never forget and it always makes your blood pressure high and your heart pump really fast when you have touched the IP and is about to turn the key to start the engine. Even when after you become expert.

BenzDiesel

that a runaway typically happens at startup? Is this condition found more frequently on turbocharged motors or is the aspiration irrelevant? On a manual shift car, a clutch stall seems to me to be a lot safer than opening the hood to block air flow, but will it always work? On the other hand, I think on my 240's air intake you could blast it with a fire extinguisher right thru the grill. Since my son is the primary driver, I want to get him prepared for this possibility. Can it happen at highway speeds? Holy crap

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You're a daisy if you do.
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84 Euro 240D 4spd. 220.5k sold
04 Honda Element AWD
1985 F150 XLT 4x4, 351W with 270k miles, hay hauler
1997 Suzuki Sidekick 4x4
1993 Toyota 4wd Pickup 226K and counting

for 99% of the times that a runaway is going to happen at start up. I know of no confirmed cases where a Bosch controlled Mercedes took off and ran away out of control after initial start up. There is always a 1 % chance that some fuel truck driver put gasoline in the diesel tanks and you filled up with a 75% mixture of gasoline to 25% diesel and your car ran away and I don't think if would run away even then. Or maybe some kid put gasoline in the oil filler hole and then started the car to cause a run away. Or maybe the primer pump will go bad and when your oil is checked you notice that it is twice the amount of oil required as measured on the dip stick and you keep driving knowing that something isn't right for your oil to be twice as full and you know you haven't added oil lately, which the extra oil is diesel fuel and could ignite and cause a run away. But for the most part, most drivers couldn't make a Mercedes diesel run away to save their life.

As far as turbo and naturally aspirated is concerned; I wouldn't think it mattered. Neither is going to run away unless the IP has been disturbed or the other 1% occurs that I just mentioned like your oil level swelling and you know you haven't added oil lately and you keep driving knowing the crankcase is over filled with something. And a run away diesel, any diesel is going to run just as out of control as any other diesel, but a turbo engine might take longer to die since it has a few stronger parts than naturally aspirated; they say.

Think about it like this. Mercedes has manufactured millions of diesels since they started making diesel powered cars in the 20's or 30's and they have never paid off a lawsuit where the car ran away and the blame couldn't be put on somebody or something else that caused the run away condition that was part of their liability as a car manufacturer. That is also why I think Mercedes dumb down diesels to the level that they do because diesels have the potential to be too fast of cars for most drivers on the road plus they dumb the cars down in order to get better fuel mileage in my opinion.

Anyway, you have no worries unless the fuel system has been disturbed or abused some how. And even then, you have to be unlucky or did something to cause the run away condition and it is going to happen at start up if you can get the car to run away.

As far as preparing your son, just make sure he knows to use only diesel fuel or anything except straight gasoline and knows where it goes and where it does not go. And let him know that if he does not disturb the IP and the car runs satisfactorially, then he has no problems, just check the oil and keep fuel in it and change the oil between 5 and 10,000 miles. Even, checking the start of delivery is not going to cause a run away. You have to tear into the IP attempting to see how it functions and not get it re-assembled properly before the engine will run away. And even then, it is no problem if you have something to kill the air supply.

It is those new computer controlled cars that have to be worried about running away these days and then the floor mats be blamed for causing the run away and the car is gas powered, but a stuck floor mat gets blamed for the semi-runaway condition while the car is in drive, which is hardly ever going to happen in an older Mercedes diesel that is Bosch controlled and be manufacturer related either Bosch or Mercedes.

BenzDiesel

Do you remove the accordion type hose from the air cleaner and block the opening to the air cleaner with the wood (or with a spray paint cap which one could easily keep in the car)?

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1985 300D Turbo
"Evolution is God's way of giving upgrades" Francis Collins

A runaway can occur without abuse, neglect, and/or warning.

NO, there are members of this forum who have experienced a run-away, while driving..

It is not common, but it does happen.

Years ago, ( 50s or 60s) there was a German diesel that i don't recall who made it, but it happened a few times that the engine ran backwards when started. The cure was the same. Stop up the air intake.

Can you give me one example of a Mercedes diesel run away and the IP had not been disturbed since calibrated at the factory? Or an example of any IP that ran away and wasn't abused, neglected, and without giving a warning.

BenzDiesel

Can you tell me who that member is that experienced a run away and the car was in gear and he/she came here to tell us about it? I'm not talking about a stuck linkage where braking and turning off the ignition could possibly shut the engine down. I mean a full blown RUNAWAY and it didn't occur at start up. It's not common, but it snows in Southern California and even when it does snow in Southern California, there is an explanation of something out of the ordinary occurred. It just doesn't happen without cause, a RUNAWAY diesel nor snow in Southern California.

BenzDiesel

The IP has little or nothing to do with most run-away MB diesel engines.

Last year I had one run-away while I was riding with the owner.
* Factory stock.
* 180K miles.
* Perfect maintenence, all documented.

The intake turbo seal failed with no warning.
Brought it to a stop, I jumped out and smashed the U tube off, used a paper back book to seal the turbo intake.
The engine was OK, owner bought a factory NEW turbo.

Year before last, I had a turbo failure on a 617 where blue smoke was more than a mosquito truck puts out and I thought the engine was destroyed. I realized that it only smoked like smoking was going out of style when I accelerated. I drove it home after three hours and replaced the turbo and the problem was solved. NO RUNAWAY and the oil had to have been passing directly into the intake through the turbo as I had to fill up with oil that I bought at a Dollar General store, STP oil. From my experiences with RUNAWAYS, you were very lucky to have a RUNAWAY and have enough patience to get the car to a stop and put it in park, then open the hood and had a telephone book handy to shut the car down and then restart the car after you knew it had ran away and could run away again, yet you drove it back to the shop. You could not have done any of that with any of the RUNAWAYS I have experienced. I would also call that incident a controlled elevation of revving rather than a true RUNAWAY. Now, if you started out saying how loud you screamed when you realized the car was RUNNING AWAY; then maybe we would be talking about the same event, which we apparently are not. Calmness and a true RUNAWAY while in gear don't even go together in a sentence, less lone in your thought processes if it actually occurs.

BenzDiesel

BenzDiesel,
Could you please give us all some details of your technical training & experience concerning diesel motors. Many on here have a life time of training and experience with diesels and some of your comments dont sit that well with those experiences. I have had 2 run aways in nearly 40 years of work. Both occurred with the motors running fully loaded. Motors in earth moving equipment are not abused, we can not afford to do that, its our money we are playing with, not a case of billing the customer!! Some motors are fitted with an air shut off to allow a run away to be controlled. While I am not that foolish to be stating % figures, experience tells me that we should be more concerned with bad drivers or brake failures than run aways.


Kellynic,
There was a German motor that was a copy of a Perkins 6/354, I think it was called a nois ( wrong spelling?), it was used in trucks, international/acco used them here. It had the problem with starting backward, I have seen 1 that was put in first & ran backwards into a wall. 2 stroke Detroits will run backwards, not for long as they have have a gear pump on the fuel supply. It starts sucking the fuel out of the head gallery, they dont have a IP, they have pumping injectors that run off a lobe on the cam.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

No offense, but experience is relative. You can change oil for a life time and be called an automotive tech and have the papers to prove it, but if your car breaks down and you are a automotive tech and you have to call somebody to come fix your car, then are you really an automotive tech? My Mercedes cars work like Mercedes Benz cars are supposed to work and when they break down, I fix them including the financing. I don't know heavy equipment diesels or Lexus or Suburu, but I do know Mercedes diesels from 1995 backwards and once you know one diesel; you just about know all of them. The problem is to learn the first one, throughly.

I agree that bad drivers should be more worried about than run away engines. Also, chances are greater that it snows in Southern California before an un-disturbed Bosch controlled Mercedes will run away.

BenzDiesel

Panic is worthless in this situation.
* Run and loose the engine.
* React correctly and quick = repair the cause/issue later.

The owner was freaking out.
The engine was screaming.
I was shouting orders.
The brakes where smoking and groaning, owner fought it down from 90 MPH under a quarter mile.


FYI:
The car was towed directly to a local MB dealer.
It was a DelRay paperback Science Fiction book.
I damaged the air filter housing removing the U-tube with brute force.
There was no patience involved in opening the hood, and smashing parts for access.
The engine was three quarts low, and it had been full fifteen minutes earlier when I was looking it over.

throw the transmission into neutral or even park then get away from the car and just let the beast blow up as long as I or no one else is injured. I'm also glad my 617 didn't run away when I had the turbo troubles. It is also assuring to know that the brakes will hold the car for awhile in RUNAWAY mode. As with all things, fear is reduced greatly once you understand what is taking place and have a plan in place. I hardly give it a second thought about a run away now, as long as it is my car that I have worked on.

BenzDiesel