Diesel Runaway
Discussion
Have hard about this rare condition where the engine continues to rev at full revs even when you turn the key off. The way to stop it is put it into a gear a tall one to stall the engine. Problem solved.
My question what happens if you have diesel runaway in an auto? You cannot stall the engine
My question what happens if you have diesel runaway in an auto? You cannot stall the engine
Welshbeef said:
Could the engine blow up before then? I mean taking off the covers to get at it the engine is going like the clappers with the risk of it throwing a rod through the block
The intake system ends with a pipe which will have an open end, usually under the front bumper. Find this beforehand so you know where to stuff the rag. It could quite possibly blow up before you can do this however.Generally speaking, small modern common rail passenger car diesels do not "explode" when they runaway on their own oil. This is because they are designed to rev to ~5krpm (in order to make the power modern cars require) At that sort of crankshaft velocity the same burn rate limitations apply when running on oil and on diesel, effectively, as rpm increases torque falls. This acts as a natural rev limiter. In the old days, or on big prime mover diesels, reving to 5krpm would result in catastrophic engine failure as the rotating / reciprocating components will not have been designed for this velocity.
That having been said, a diesel the runs away until it has used it's own oil up will typically still be ruined, as oil starvation will generally lead to journal bearing failure. (and uncontrolled combustion can melt things like turbo's valves and damage pistons etc)
That having been said, a diesel the runs away until it has used it's own oil up will typically still be ruined, as oil starvation will generally lead to journal bearing failure. (and uncontrolled combustion can melt things like turbo's valves and damage pistons etc)
Not sure i would want to be anyway near one if it happened!
http://www.youtube.com/watch?v=5zx3qKX_Pno
http://www.youtube.com/watch?v=5zx3qKX_Pno
Welshbeef said:
Could the engine blow up before then? I mean taking off the covers to get at it the engine is going like the clappers with the risk of it throwing a rod through the block
I had it twice on an Astra .I managed to stall engine both times ,but was unlucky enough to damage a rocker. A chat with one of the breakdown guys revealed that excess oil was usually the cause .This one was fresh out from a service . 
jason s4 said:
Not sure i would want to be anyway near one if it happened!
http://www.youtube.com/watch?v=5zx3qKX_Pno
Do de doo, just gonna check the glovebox for a rag then I'll pop the bonnet and block the air intakehttp://www.youtube.com/watch?v=5zx3qKX_Pno
I think i've posted this before but a trafpol I know got into his company 535D at the start of his shift and was greeted with a message telling him to add a litre of oil. Being the cautious type he took a picture of the dash and added a litre of oil.
All was fine until he recieved an invite to an incident on the M1 so he proceeded to use the upper regions of the rev range. After a short time at .5 beyond lightspeed he noticed an oily smell coming through the vents, a few seconds later there was smoke in the cabin. So he pulled onto the hard shoulder and sure enough it was a runaway engine, he knocked the gearbox into neutral exited the car and retired to a safe distance.
It turned out the oil level switch was defective and it asked for oil it didn't need. BMW tried every excuse possible to avoid paying for a new engine until they were shown the picture and they relucantly coughed for a new engine.
All was fine until he recieved an invite to an incident on the M1 so he proceeded to use the upper regions of the rev range. After a short time at .5 beyond lightspeed he noticed an oily smell coming through the vents, a few seconds later there was smoke in the cabin. So he pulled onto the hard shoulder and sure enough it was a runaway engine, he knocked the gearbox into neutral exited the car and retired to a safe distance.
It turned out the oil level switch was defective and it asked for oil it didn't need. BMW tried every excuse possible to avoid paying for a new engine until they were shown the picture and they relucantly coughed for a new engine.
Since i assume Scrapheap Challenge would be popular viewing on here, on the first tour around the country program they did, i can't remember the title of it, anyway the big yellow truck built by the farmers did just this after it was messed around with to much, lol it was brilliant to watch.
Welshbeef said:
Have hard about this rare condition where the engine continues to rev at full revs even when you turn the key off. The way to stop it is put it into a gear a tall one to stall the engine. Problem solved.
My question what happens if you have diesel runaway in an auto? You cannot stall the engine
In which case you also runawayMy question what happens if you have diesel runaway in an auto? You cannot stall the engine
TheEnd said:
Codswallop said:
^^ He did the only thing he could. One does not simply stall a 535d.
sorry
I've heard the one way to stop one is to hitch it to another pulling in the opposite direction.sorry
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