I was reading whunter's Wiki on runaway diesels today, and it got me thinking...

I'm guessing an excessive oil consumption and a smoky idle could be tell-tale signs of such a condition. What sort of an oil consumption rate would be considered normal on our Benzes? Mine seems to use up about a quart between 5,000-mile oil changes, which includes several leaks I have at the moment.

Also, does switching to a fully synthetic oil (i.e., Mobil 1 Turbodiesel Truck) on a high-mileage Benz increase chances of encountering a runaway diesel? As many of us have seen, switching to synthetics tends to make the tired old seals leak oil externally. But are there any internal rubber seals (for example, in OM617) whose leakage could lead to a runaway (i.e., valve stem seals, turbocharger, etc)?

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84 300SD - bought in April '06 with 237,000 mi

The problem would not be only the seals, but all the internal crud (carbon build-up etc) that'd probably come loose after oilchange. Synthetic oil can really wash stuff off an old engine and that is not always desirable. Clogging up internal oil channels would lead to more or less catastrophic failures easily... I'd be quite cautious about just changing the oil to synthetic type. Actually I wouldn't do it at all, at least not without taking the engine apart enough to determine how clogged it is, and, if necessary, making it less clogged.

1qt in 5000 miles is actually good, especially with external leaks.

You would have to be in the 1qt per 1000mile or less range before runaway would be an issue.

The chances of seeing a true runaway are 1:1,000,000. You have a better chance of winning the lottery than your personal car suddenly running away on its own without you causing it.

Hang a 17mm wrench off one of the injection lines, "rip and unscrew in case of emergency"

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1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

Won't stop a runaway diesel as runaway diesel is running on crankcase fumes from intake breather hose, not fuel supplied by injection pump. The way to stop these is to plug the air intake to engine. Do not use your hand to do this, you might loose a largish piece of skin.

I don't recall seeing any posting on this board concerning a 617 running on its own engine oil. All runaways have been on diesel fuel. There was a recent instance in which a European poster thought he might be facing that problem in a 616 in a van but I don't think that issue was ever decided. Therre was a possibility he was sucking engine oil thru the vacuum pump.
Lots of people here have driven very high mileage 617's with low compression and high blowby but no runaways. I'd say Lance might even be overestimating the odds it will happen.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I was under the impression that a blown turbo oil seal could dump enough areated fuel to cause a runaway in a 617... not so?

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With oil consumption that low you definitely do not have to worry about this. I had a 240D which consumed a quart every 300-400 miles and did so for years until I sold it to a guy who "forgot" to check it for a while and ran it dry. Even then is seized before running away.

A quart every 5000 miles is excellent, even some new cars use more than that!

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Yup, runaways almost never happen, except for very special circumstances. Blocking the air intake will stop it anyway, no matter what type of runaway it is. Diesel fuel runaway is much more usual than crankcase fume runaway, didn't know that they're called the same - thought that "runaway diesel" would be the perpetuum mobile-type thing that happens very rarely, if large amount of air-oil mixture with right ratio from crankcase goes to intake, causing revving up, causing more air-oil mixture to go to intake, etc...

But, as said, they rarely happen at all. Never heard of one happening with naturally-aspirated engine, and of two incidents on turbocharged engines because of oil leak in turbo, as pointed out by vstech. Not on 617's though.

Our OM615 has massive blowby, enough to throw the filler cap off if it's open, left on the filler hole. No any signs of it ever even trying to running off. It doesn't even consume that much oil, 1-1.5 quart per 5000km. The oil looks and feels like oil all the way through change interval, no signs of water or diesel in it. No real idea what's going on there. Will look at it as soon as any major repair requires taking the engine apart - hopefully not too soon

That's a good point. However, I've already switched from Delvac 1300 to Rotella Synthetic (well, "mostly" synthetic) since about a year ago. I hope nothing catastrophic happens. I bought Mobil 1 Turbodiesel Truck oil for this oil change, which is fully synthetic. I will run it, but I'll probably go back to Rotella after that because Mobil 1 is way too expensive... $22 per gallon for Mobil 1 versus $16 per gallon for Rotella Synthetic in Wally Mart... I'd go back to Delvac 1300, but every 3,000 oil change is too often for me, so I used Rotella synthetic because it is safe over 5,000 mi interval (and even longer, according to Brian...)

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84 300SD - bought in April '06 with 237,000 mi

I've used both Rotella synthetic and M1 5W40 in mine with 5000 mile changes. All old wives tales aside, there is no downside to using synthetics and the cold weather starting is much better.

Many things can cause a run away, a failed governor, IP, turbo seals. The engine has to be able to suck enough oil out of the crank to run.

The best way to stop one is a peice of wood over the intake or a C02 fire extinguisher.

Run aways are pretty rare, I have only seen/heard of a handfull. One was a on a freshly overhauld 16V92TA. It was the port engine on an Ocean 63. The owner was running the boat at WOT, and the throttle failed so he couldn't throttle down. So insted of wheeling the boat around and thinking about it for a minute, he took it out of gear! So it went from maximum load to zero in a second, the smoke was amazing, looked like the boat was on fire. Finnaly after a couple of minutes the engine blew apart.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Indeed. I use Delvac MX 15/40 at summer - when it gets cold, you could probably cut that stuff with knife. It all depends on amount of buildup inside engine. Many people have successfully just changed over from mineral to synthetic, my cautiousness is for some part my own paranoia to avoid destroying the engine... Oh, and of course change the oil filter every time you change oil! Actually, now that I think of it, one could change the filter a couple of times during oil change interval after changing from mineral to synthetic. Filter stops crud, anyway. I suppose the OM61x engines have a "safety valve" making oil from pump bypass the filter if filter is too clogged to let oil through?

The 603 can consume one quart every 25 miles and it won't cause a runaway. It consumes one gallon of fuel to go that distance and one additional quart still remains negligible.

Furthermore, the engine doesn't really like to burn the oil unless it's properly atomized. In my situation, I was in danger of hydrolocking the engine on liquid oil...........not causing a runaway.

I also have NEVER heard of an MB diesel running away on it's own oil supply. This is a phenomenon that is present with the old style Detroit diesels.

The only runaway threat is startup after IP service. As long as you get linkage movement when applying vacuum to the shut off solenoid, it is highly unlikely that you will not have a runaway.

SOOooo..... There are two things to do after IP service; check for linkage movement while applying vacuum to the shutoff solenoid, and then stand by with a 17MM open end upon start up. If it runs away, start loosening lines immediately. Cutting fuel line(s), forget it. Having a phone book for the air intake, not unless the air cleaner is off. Just keep the 17MM in your hand and forget all the other bunk.

BTDT,