Diesel Engine Runaway 1.6 TDI POLO

[Grizzy]

Its been awhile since since i have posted, as my 2011 1.6 TDI POLO has been running amazingly until last night.....

And so the story beings...... I think i may have a RUNAWAY!

Last night whilst driving my 2011 1.6 TDi Polo, the car decided i was not longer in control and it wanted to continue revving its self (red line pinging) until i put the car in neutral, came to a screeching stop, and turned the ignition off!

To my amazement, the engine continued to run at a ridiculously high RPM after the ignition had been turned off, made 4-5 loud tick/bang noises, then decided to die. Not realising what had just happened, and being in a bit of shock, i got out of the car with the two friends i was with and proceeded to open the bonnet. To my amazement the engine looked fine, fluids were fine, oil was fine, everything looked in order. As i was only a few streets away from my home i decided to try and start the car again. Engine started a bit rough and the moment i tried to drive it, white smoke started pouring out of the exhaust. So i turned the car off again and proceeded to push my Polo home.

Once home i decided to do a bit of research on what had just happened, as one of the friends with me had suggested it might be a RUNAWAY DIESEL! From what i can tell a Runaway Diesel is a rare occurrence where an oil leak (i.e. Turbo, Air intake via crankcase) turns into a feedback loop, constantly over fuelling the engine until it runs faster and faster, thus destroying the engine due to mechanical failure.

So my questions are:

Does my problem sound like a Diesel Runaway that i somehow stopped before it destroyed my engine?
Could it just be a leaky Turbo?
Or am i completely off par, an it might actually have something to do with the Electronic Accelerator?

My beloved Polo is on a tow-truck, on its way back to the dealer as we speak. Fingers crossed, what ever has happened is covered under my warranty!

Everyones help is much appreciated!

Thanks,
Grizzy

[Kiels3927]

A friend (also with a diesel) regularly sends me links like this: https://www.youtube.com/watch?v=rLzf3ItkbOE

[Ryeman]

If your 3 yr warranty is still active you shouldn't have a problem and in fact you should get a cutesy car to tide you over.
At the moment I think the last thing VW needs is any more bad publicity so you should be fine.
Keep us informed.


Sent from my iPad using Tapatalk

[wai]

Diesels can run away if there is a fuel supply, even if the ignition is turned off because there is no electrical ignition as such.

Check your oil level as it can get high and this can then produce enough vapour to keep the engine running. In fact, ANYTHING that allows a fuel source to enter the engine will keep a diesel running, so leaks from things like a failed head gasket where the failure allows oil from an oil gallery to the combustion chamber will be enough. The engine will not necessarily run smoothly, but it will run.

The best way to stop it is to put it in a high gear and try and stall the engine.

[Grizzy]

Thanks for all the input guys!

An Update from the Service Centre:

"The car needed an ECU update, and was over filled with oil"

I drove my Polo on a 4 hour round trip, to and from the Brisbane Airport, before everything happened that night.

With the oil being at a normal level before i left home, could it really have expanded that much? The dealer seems to think it could have something to do with too many cold starts and short trips, as they say to me every time i have a problem! Yet the car gets a good 3 hour trip to Brisbane almost every month, and a good 30 minute run to and from work ever day.

Is there something i am missing? Or am i being strung along?

[wai]

It depends on a number of things.

Oil will expand.

You can get some excess diesel finding its way past the piston rings but it would see a gradual rise in oil level.

The level must be checked on level ground, although a well designed sump should not see too great a variation. Also, you need to let the oil drain from the engine before checking the level.

Also, an incorrect dipstick can cause problems.

[gldgti]

If the dealer has said the oil was overfilled, I would be interested to know 'who filled it'.

It does sound like you had a runaway. There is an air throttle in the modern TDI's that serves several functions but I'm not sure if it is designed well enough to halt an engine runaway.

Either way, it seems like now you have a blown headgasket if there is white smoke (steam?) coming out of the exhaust.

I would be thinking engine rebuild/new engine.

[Grizzy]

If the dealer has said the oil was overfilled, I would be interested to know 'who filled it'.

It does sound like you had a runaway. There is an air throttle in the modern TDI's that serves several functions but I'm not sure if it is designed well enough to halt an engine runaway.

Either way, it seems like now you have a blown headgasket if there is white smoke (steam?) coming out of the exhaust.

I would be thinking engine rebuild/new engine.

Last time the oil was topped up was when it was last serviced. It was on the high side of the 'crosshatched' section of the dipstick, but i had been told that was ok.

Received my car back from the dealer today saying everything appeared ok, besides the high oil and a ECU upgrade. As for the smoke, i was told it had gotten better (which it had almost disappeared driving home) as it was only residual oil being burnt off?

My concern is in getting the car back in just under a day, has everything really been assessed?

Im also now freaking out about a potential diesel leak, into the sump, thus effectively diluting and increasing the amount of oil withheld.....

[Skooter]

Might be worth a look at my post Sump Level Rise in '10 103 TDI PD in this Diesel section. I drianed 8.5L of oil from my sump - long story short, VAG agreed to check under warranty and Preston Motors Skoda (now lost their dealer status!) determined it was an overfill by Richmond Skoda who had last serviced the car (which they'd emphatically denied when I questioned them).

If excessive oil in the sump was going to cause engine runaway, mine would have done it many times over - over a 15,000km period before the overfill was discovered it had plenty of very fast driving, loads of congested city running. I was worried it was sump leakdown, but not the case. Since last fill the level is static (12000km).

If I had a car under warranty and it did what yours did I would be a) very upset and b) very worried that damage had been caused somewhere. as long as you have the record of the issue and the work done, you should be covered for future possible probs.

[gldgti]

My concern is in getting the car back in just under a day, has everything really been assessed?

It would seem unlikely.

[Finchley]

Hi Grizzly

My daughter was driving a 2011 Polo TDI on the M3 motorway in Melbourne when it spontaneously accelerated to a speed of 130km/hr despite trying to break it. Fortunately the engine blew up and she was able to bring the car to stop safely on the side of the motorway. This event took place in July this year.

We had the car taken to Doncaster Volkswagen which diagnosed it as a case of diesel runaway or diesel run on and told us the car had been over-oiled. We have not put any oil in it. The car is a write off but fortunately my daughter is safe but remains traumatised.

Im interested to read that your service technician advised that an ECU upgrade was part of the fix. Are you able to provide any more details on the fix or what caused your event? Have you had any problems with the car since?

I would love to hear from you or anyone else who has experience diesel run-on or diesel run-away, which may be rare fault but is incredibly dangerous.

[Transporter]

Welcome to the forum Finchley.
You most likely not get the respond from Grizzly, the last time he logged in was in 2014.

In no way by the text bellow I’m having a go at you, just trying to help you in the future to void a similar situation again.

ECU upgrade or not.
Here is what possibly went wrong with your daughter’s TDI Polo.
Someone during service put too much oil in the engine, but my experience is the the car owners often don’t check the oil level properly and then when topping it up, they put way too much of engine oil in, like 2-3 or even 4L of oil. Of course, when they recheck the oil level on dipstick it seems to be just about right, because the car was parked on uphill and they happily drive of and for very long time without checking the oil level, until something goes wrong. Bummer yeah?

The most likely runaway in your case, in many cases could be prevented (it wouldn’t happen) if the car owners check the oil level as they should, once a week, every 500km or when refueling. Also, there the flap in the throatle body which should stop the runaway diesel engine, it is the only purpose of that flap to be there and if it wasn’t working, someone didn’t do his job properly while servicing your daughter’s car, hence the importance of proper servicing by qualified mechanic and not DIY or back yarder self educated by Mr Google.

Of course they could also be leaking injector(s), but the check engine would come on and again the driver would see the increased oil level 500km later when checking the engine oil level.

[Finchley]

Welcome to the forum Finchley.
You most likely not get the respond from Grizzly, the last time he logged in was in 2014.

In no way by the text bellow I’m having a go at you, just trying to help you in the future to void a similar situation again.

ECU upgrade or not.
Here is what possibly went wrong with your daughter’s TDI Polo.
Someone during service put too much oil in the engine, but my experience is the the car owners often don’t check the oil level properly and then when topping it up, they put way too much of engine oil in, like 2-3 or even 4L of oil. Of course, when they recheck the oil level on dipstick it seems to be just about right, because the car was parked on uphill and they happily drive of and for very long time without checking the oil level, until something goes wrong. Bummer yeah?

The most likely runaway in your case, in many cases could be prevented (it wouldn’t happen) if the car owners check the oil level as they should, once a week, every 500km or when refueling. Also, there the flap in the throatle body which should stop the runaway diesel engine, it is the only purpose of that flap to be there and if it wasn’t working, someone didn’t do his job properly while servicing your daughter’s car, hence the importance of proper servicing by qualified mechanic and not DIY or back yarder self educated by Mr Google.

Of course they could also be leaking injector(s), but the check engine would come on and again the driver would see the increased oil level 500km later when checking the engine oil level.

Hi Transporter, thanks for your reply.

We always have our cars serviced in accordance with the log books but I never check oil between services unless the oil light comes on. My daughter would struggle to open the bonnet let alone know how to check and add oil to the engine. The last service the car had was at a Volkswagen dealer.

She said a light had come on. It was the DPF light.

Any idea on the ECU upgrade that Grizzy mentioned in his post?

Would you be able to send grizzy my email and ask him to contact me?

Thanks for your help.

[Rebuild]

Welcome to the forum Finchley.
Also, there the flap in the throatle body which should stop the runaway diesel engine, it is the only purpose of that flap to be there.

i always thought it's an anti shudder valve, to stop the engine knocking when you switch off.

Finchley, you can try Private Messaging Grizz. Left click his user name and select PM

[bloödstorm]

Scary story, Finchley. I suggest it may have undergone an excessive number of active DPF regenerations. Each regeneration lets a small amount of diesel into the crankcase, diluting the oil and increasing its level, leading eventually to the situation Transporter described with overfilled oil. The DPF statistics can be read via OBD.