i wonder what’s happening here 
d4c24a:
i wonder what’s happening here
Dunno…but i would not want to be driving through it on a single carriageway…and the driver is doing what i would do, walk the other way.
BUT…i would have switched the motor off first.
Could be a blown turbo■■?
Looks like a runaway engine. The engine starts fuelling from its own oil. No way to stop it bar blocking the air supply and stalling the engine.
By the time it’s got to that stage, the engine is toast, so just leave it until it melts itself
You cannae switch that off rapper that’s a runaway engine, the only thing that might stop it would be a co2 fire extinguisher into the intake. I’d just walk away and phone the depot for a tow truck to the scrappy
Where’s BKing when you need him, he know’s all about diesel engine runaways!
Impossibility according to him, it doesn’t / cant happen.
Gembo:
Where’s BKing when you need him, he know’s all about diesel engine runaways!
Impossibility according to him, it doesn’t / cant happen.
i posted especially for him to give his expert diagnosis 
Runaway, only chance you have to save it is clogging the air intake.
I saw a book on diesel engines in WHSmiths once, just to make you aware of my level of expertise in this subject.
Surely if you’re drawing engine oil into the combustion chamber, you’ve a pretty serious problem already? Isn’t runaway just a symptom of the problem rather than the problem itself?
Captain Caveman 76:
I saw a book on diesel engines in WHSmiths once, just to make you aware of my level of expertise in this subject.Surely if you’re drawing engine oil into the combustion chamber, you’ve a pretty serious problem already? Isn’t runaway just a symptom of the problem rather than the problem itself?
It can be caused in one of 2 ways. Either the engine breaths heavily due to knackered piston rings and ingests the resultant excessive crankcase gases and oil mist from the breather system or more commonly the oil seal and bearing on the shaft of the turbocharger fails and you’ll then get lube oil pumped straight into the inlet manifold by the engines oil pump via the turbo.
Because a diesel’s compression ratio will raise the charge air on the compression stroke to just over 1000 fahrenheit the resulting heat will ignite and combust any oil / fuel ingested into the cylinder.
Gembo:
Captain Caveman 76:
I saw a book on diesel engines in WHSmiths once, just to make you aware of my level of expertise in this subject.Surely if you’re drawing engine oil into the combustion chamber, you’ve a pretty serious problem already? Isn’t runaway just a symptom of the problem rather than the problem itself?
It can be caused in one of 2 ways. Either the engine breaths heavily due to knackered piston rings and ingests the resultant excessive crankcase gases and oil mist from the breather system or more commonly the oil seal and bearing on the shaft of the turbocharger fails and you’ll then get lube oil pumped straight into the inlet manifold by the engines oil pump via the turbo.
Because a diesel’s compression ratio will raise the charge air on the compression stroke to just over 1000 fahrenheit the resulting heat will ignite and combust any oil / fuel ingested into the cylinder.
My old petrol sierra used to run on so badly I could be sat in my living room with the thing still chugging away outside! I stripped it down and cleaned all the carbonised crap out of the cylinders, which pretty much cured it.
Back to the lorry, in either of those scenarios the engine would be written of, wouldn’t it? Or is a new turbocharger actually economical?
Captain Caveman 76:
Gembo:
Captain Caveman 76:
I saw a book on diesel engines in WHSmiths once, just to make you aware of my level of expertise in this subject.Surely if you’re drawing engine oil into the combustion chamber, you’ve a pretty serious problem already? Isn’t runaway just a symptom of the problem rather than the problem itself?
It can be caused in one of 2 ways. Either the engine breaths heavily due to knackered piston rings and ingests the resultant excessive crankcase gases and oil mist from the breather system or more commonly the oil seal and bearing on the shaft of the turbocharger fails and you’ll then get lube oil pumped straight into the inlet manifold by the engines oil pump via the turbo.
Because a diesel’s compression ratio will raise the charge air on the compression stroke to just over 1000 fahrenheit the resulting heat will ignite and combust any oil / fuel ingested into the cylinder.My old petrol sierra used to run on so badly I could be sat in my living room with the thing still chugging away outside! I stripped it down and cleaned all the carbonised crap out of the cylinders, which pretty much cured it.
Back to the lorry, in either of those scenarios the engine would be written of, wouldn’t it? Or is a new turbocharger actually economical?
My Hillman Avenger 
used too do that.
Thought it was more of a timing issue,called “pinking”
Suedehead:
Captain Caveman 76:
Gembo:
Captain Caveman 76:
I saw a book on diesel engines in WHSmiths once, just to make you aware of my level of expertise in this subject.Surely if you’re drawing engine oil into the combustion chamber, you’ve a pretty serious problem already? Isn’t runaway just a symptom of the problem rather than the problem itself?
It can be caused in one of 2 ways. Either the engine breaths heavily due to knackered piston rings and ingests the resultant excessive crankcase gases and oil mist from the breather system or more commonly the oil seal and bearing on the shaft of the turbocharger fails and you’ll then get lube oil pumped straight into the inlet manifold by the engines oil pump via the turbo.
Because a diesel’s compression ratio will raise the charge air on the compression stroke to just over 1000 fahrenheit the resulting heat will ignite and combust any oil / fuel ingested into the cylinder.My old petrol sierra used to run on so badly I could be sat in my living room with the thing still chugging away outside! I stripped it down and cleaned all the carbonised crap out of the cylinders, which pretty much cured it.
Back to the lorry, in either of those scenarios the engine would be written of, wouldn’t it? Or is a new turbocharger actually economical?My Hillman Avenger
Thought it was more of a timing issue,called “pinking”
I always thought pinking was caused by preignition of fuel/air mixture in the chamber, pushing the piston back down before it reached full compression.
Happy to be corrected on that. I’ve had zero training on engines and only know what I’ve figured out from Haynes manuels and getting greasy!
Runaway.
By the time the engine has finished eating its way through all the available oil and vapour it’s scrap - pure and simple.
If you’re lucky, you’ll get away with ‘just’ a complete new engine: if you’re unlucky (and this scenario is far more likely) the runaway will end up either melting – and and taking a lot of the ancilliaries with it – or, and far more likely, blowing itself apart and destroying most of the truck in the process.
Keep an eye on hte For Sale ads and if you see “merc, one owner, needs slight attention to engine” … 
Captain Caveman 76:
in either of those scenarios the engine would be written of, wouldn’t it? Or is a new turbocharger actually economical?
Pretty much a dead cert unless your quick enough to plug the inlet with a large piece of rag to starve it of oxygen.
Would take some doing though as you’d more than likely have to remove some pipe or some such to do it by witch time its damaged from over speed anyway.
Even trying to stall them in gear normally just burns the clutch out. In reality the engine will run itself dry of oil and seize.
Edited to say, win-stone beat me to it but you get the idea.
Captain Caveman 76:
My old petrol sierra used to run on so badly I could be sat in my living room with the thing still chugging away outside! I stripped it down and cleaned all the carbonised crap out of the cylinders, which pretty much cured it.
That’s a little different. What used to happen with the old ford pinto was that red hot carbon would ignite the petrol after you switched off the sparks from the spark plugs, ie the ignition key and the engine would run on.
Pinking or ‘detonation’ for want of the correct word is when the fuel is ignited before the spark from the plug does it. This is bad as its uncontrolled burning of the petrol and causes melted pistons and exhaust valves and sometimes even knocks out big end bearings.
Its normally caused by very lean petrol and air mixture. (to much air, not enough fuel) Excess carbon build up will also cause it when it glows red and ignites the fuel, again, before the spark plug does.
Cheers for the info Win-Stone and Gembo.
Guess I’m ■■■■■■ invisible then…, 
Quickest way into the air intake to stuff, probably fairly bulky item of clothing, in on most trucks is to tilt the cab slightly.
109LWB:
Guess I’m [zb] invisible then…,
Who the ■■■■ said that?
If you catch that problem immediately can’t you stalk the engine and stop it? I’m guessing that once it’s well away on oil you’ve no option other than getting out and running.