PDA

View Full Version : Diesel Engine Runaway


Harold Gough
27th April 2019, 09:38 AM
My Peugeot diesel was giving me an excess engine oil warning. This probably resulted from a failed burn-off of the exhaust filter prior to the cause being remedied. Such a failure is know to push diesel into the sump.

Thinking this was just a minor issue, I have arranged for the oil to be drained, a new filter fitted and the oil replaced to the required level. My mechanic told me of the possible consequences of the excess oil, which could start a runaway process when it gets sucked into the cylinders:

https://en.wikipedia.org/wiki/Diesel_engine_runaway

Harold

Jax
27th April 2019, 09:54 AM
My Peugeot diesel was giving me an excess engine oil warning. This probably resulted from a failed burn-off of the exhaust filter prior to the cause being remedied. Such a failure is know to push diesel into the sump.

Thinking this was just a minor issue, I have arranged for the oil to be drained, a new filter fitted and the oil replaced to the required level. My mechanic told me of the possible consequences of the excess oil, which could start a runaway process when it gets sucked into the cylinders:

https://en.wikipedia.org/wiki/Diesel_engine_runaway

Harold

Thanks for posting this interesting info Harold. It seems to be very concerning especially as we have 2 Peugeot diesel vehicles one 10 yrs old and a 3 yr old. The possible consequences detailed on Wikipedia are even more worrying *yes

Jax

peak4
27th April 2019, 10:18 AM
I used to have a 2 1/4 diesel engine in the Landrover, which I eventually replaced witha 3.5 V8 when it started running on its own engine oil.
Compression was quite low, with high crankcase pressure allowing oil into the combustion chamber, when I would get runaway and large clouds of smoke.
Fortunately a manual gearbox, so I could stall the engine and let it cool down for a while before continuing on my journey. ;)

It's a serious problem with an auto box as one can't easily stall the engine, the only real solution being a rag or suitable fire extinguisher up the air inlet, but it's always a bit precarious getting that close to a runaway engine.

The one to watch out for with modern turbo diesels, is the seals in the turbo starting to wear out. this allows an oil mist into the air inlet, again leading to runaway. If the inside of the intercooler starts getting too contaminated, make sure you get the problem investigated.

Ricoh
27th April 2019, 10:25 AM
The runaway Diesel engine often comes to a sticky end, eventually resulting in self destruction given no electronic rev. limiting and a gallon or more of sump oil to consume.

-> Brakes on hard, first gear, up against a wall try stalling the engine if possible. NB I'm not at all qualified to offer advice, I'm just saying what I might try in similar circumstances.

wornish
27th April 2019, 03:01 PM
This is scary stuff.

Naughty Nigel
27th April 2019, 03:05 PM
Diesel engine runaway is a well known problem in diesel engines big and small. Some industrial engines, such as fork lift engines have suffered this in flammable environments with disastrous consequences. These are now fitted with air intake limiters to cut off the air supply in runaway situations.

In an automatic the only thing you can do is to put the gearbox into neutral and let the engine blow itself to pieces. This doesn't usually take long.

JLR used to provide free oil changes where the engine oil level became excessive owing to failed regenerations. (This were recorded in the black box.) The problem was solved around ten years ago with an ECU software update.

Jim Ford
27th April 2019, 05:47 PM
I was a test inspector at the Rolls Royce Small Engine factory, involved with testing Gnome engines, used in helicopters:

https://www.rolls-royce.com/products-and-services/defence/aerospace/rotary/gnome.aspx#/

Oil was cooled on the engine in a sandwich box sized cooler where the engine fuel flowed past a matrix of tubes carrying the oil. There was an incident where the matrix ruptured and engine oil was pumped into the fuel system. The engine ran away and the tester was unable to shut the engine down by cutting off the fuel supply - it was running on the oil. The faster the engine ran, the faster the oil pump pumped oil into the fuel burners and the engine eventually burned out.

Jim

Harold Gough
27th April 2019, 07:15 PM
This is scary stuff.

The main thing it that the ignition key and the ECU will become irrelevant. Starving the engine of air would be the most cost-effective solution but sacrificing the clutch to stall it is the next best.

On the positive side, only about half the cars in the UK are at potential risk.*chr

Harold

Graham_of_Rainham
27th April 2019, 08:05 PM
It would seem that there are several of us that have experienced this.

I used to manage a fleet workshop and got a call to come and see something “interesting”...

An old track vehicle, with a multi-fuel engine was running quite fast and the fitters explained that they had closed the fuel valve but it was running on its own oil. It eventually stopped when it couldn’t get enough oil to run and there was no damage. That was down to a leaking oil cooler.

I have seen others, where Con-rods have come out the side of the block and crankshaft split into bits...

:eek:

wornish
27th April 2019, 08:48 PM
Think I might switch back to petrol.
I have a diesel with an auto gearbox and no high-level oil warning light. I checked that this afternoon.

Naughty Nigel
27th April 2019, 09:37 PM
Think I might switch back to petrol.
I have a diesel with an auto gearbox and no high-level oil warning light. I checked that this afternoon.

As long as you keep an eye on it there should be nothing to worry about. I had high-ish oil level on a couple of occasions but nothing went wrong. I got free oil changes, a software update and all was well.

MJ224
28th April 2019, 07:44 AM
My only experience with a dodgy diesel was with my boat. I motored to my mooring, tied up switched off the engine and cracked open a beer with my neighboring boat.

To my surprise, the old Bukh 20 just started all by itself. Must have been a fault in the control panel I guess. And it was reving quite high. I tried the Stop solenoid to no effect, panic was setting in a little now...Next I tried cutting off the air supply at the air filter to no effect.

My last and only solution was to get at the back of the engine, (two hatches and liferaft removal), and cut the fuel supply. I undid the fuel line just before the fuel bowl.

I then waited for 15 minutes whilst the engine used up the fuel bowl's worth of diesel...………..Now that is economical or what...…………..*chr

All fixed now, and the boat is up for sale/sail...…..:)

shenstone
28th April 2019, 08:31 AM
I used to have a 2 1/4 diesel engine in the Landrover, which I eventually replaced witha 3.5 V8 .

That's and expensive option isn't it? Why not a 200/300 TDi which would be a much better mpg. Mine went from the V8 to the 300 and I get nearly double the range

Regards
Andy

Harold Gough
28th April 2019, 10:34 AM
Think I might switch back to petrol.
I have a diesel with an auto gearbox and no high-level oil warning light. I checked that this afternoon.

My warning is a code on the odometer just after I switch on.

Harold

Harold Gough
28th April 2019, 10:35 AM
My only experience with a dodgy diesel was with my boat. I motored to my mooring, tied up switched off the engine and cracked open a beer with my neighboring boat.

To my surprise, the old Bukh 20 just started all by itself. Must have been a fault in the control panel I guess. And it was reving quite high. I tried the Stop solenoid to no effect, panic was setting in a little now...Next I tried cutting off the air supply at the air filter to no effect.

My last and only solution was to get at the back of the engine, (two hatches and liferaft removal), and cut the fuel supply. I undid the fuel line just before the fuel bowl.

I then waited for 15 minutes whilst the engine used up the fuel bowl's worth of diesel...………..Now that is economical or what...…………..*chr

All fixed now, and the boat is up for sale/sail...…..:)

In correct procedure. You should have sunk the boat! :D:D:D

Harold

Jax
28th April 2019, 01:54 PM
In correct procedure. You should have sunk the boat! :D:D:D

Harold

Is it not also correct procedure for the Captain to go down with his boat ? :D


Jax

peak4
28th April 2019, 08:39 PM
That's and expensive option isn't it? Why not a 200/300 TDi which would be a much better mpg. Mine went from the V8 to the 300 and I get nearly double the range

Regards
Andy

Ah, but this was in 1988 when alternative diesels were thin on the ground.
My Disco 1 is a 300TDi.
The Lightweight doesn't do many miles these days, and is far from standard.
High Ratio transfer box, giving approx RangeRover gearing in high box and Series gearing in low, so best of both worlds.
This is mated to a Borg Warner 66 out of a Series 2 Jag, and slowed down by TI Console disks at the front and LWB drums at the rear.