Audi A4 Burning Oil and uncontrollably revving

Prodigy38

Hi,
Recently my 03 audi a4 1.9 tdi has been having a problem burning oil, I was driving along at 100km an hour and it then starting revving uncontrollably, I pressed the clutch and took my foot off the accelerator but it kept revving higher and higher. I managed to turn off the ignition. there was a lot of blue smoke and when i turned it on it done it again. Eventually i let it cool down and i turned it on and a puff of blue smoke came out again. When im driving i can smell oil burning and smoke everytime i turn it on. Anybody know whats wrong or had this happen to them. I already was at a friend who is a mechaninc and found there was a crack in a cylinder which he fixed. The problem has still been happining though. Any help?

Ronnie Beck

Turbo seals are gone.

MarkR

Runaway Diesel?

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

toastedpickles

Could be one of these

Worn valve guides or seals
Wear in power assemblies (cylinders, piston rings, ring grooves)
Cylinders glazed
Piston ring sticking
Incorrect grade of oil (eg oil too thin, and getting past the rings)

ljpg

i rekon your turbos on the way out or as ronnie beck said the seals are gone,pull off the pipe going into your intercooler,i bet ya its full of oil

tf19

Audi A4 Burning Oil and uncontrollably revving ?

Sounds like you have Feltspek-itus

dgt

Runaway diesel. Sort it before your engine gets goosed or causes a serious accident

jimgoose

As the lads say, it's a runaway diesel. Basically, things (piston rings, turbocharger seals, that kind of thing) are worn in there to the extent that it's running on its own lubricating oil, the supply of which is uncontrolled and hence the mad revving. Don't restart it until it is properly sorted - if it doesn't throw a rod or something it'll burn up all the oil and completely crap itself.

ugglasdav

i would get this sorted ASAP, if the problem is left you will find yourself with the engine no turning off when you turn the ignition off, this will cause the engine to rev high, use up all the oil in the engine until its all gone, and boom, your engine will be destroyed.

If this happens, block the air flow to the engine, put a rag over the inlet pipe going to the turbo

Nissan doctor

@OP. I'd be interested to know how your mechanic friend fixed a crack in a cylinder since this would either require a new engine or major machine work.

Anyway, as has been said, it sounds like your suffering engine run on caused by oil making its way into the cylinders. For the engine to run on(rev) like you describe the oil has to be under high pressure so the turbo is really the only place it can be coming from.

If piston rings etc were worn badly enough to allow that much oil into the cylinders then the compression would be way down and the engine would barely start and would be seriously down on power if it did.

dgt

OP, how much oil has the engine got? Once read of a Xsara that sucked it's oil through the breather after it was overfilled

RandomAccess

These are hard to watch, but show how it might end up in a destroyed engine, seized up entirely.

https://www.youtube.com/watch?v=SiBxwGQQ8Js

https://www.youtube.com/watch?v=5zx3qKX_Pno

The only way to stop it is to try stall the engine as soon as it runs away. Easier said than done I should think particularly on an HGV

Matt Simis

RandomAccess wrote: »

These are hard to watch, but show how it might end up in a destroyed engine, seized up entirely.

The only way to stop it is to try stall the engine as soon as it runs away. Easier said than done I should think particularly on an HGV

Indeed this is what it sounds like. Just thinking though, how does one cut out (as in stall) an Automatic transmission Diesel?!

RandomAccess

Matt Simis wrote: »

Indeed this is what it sounds like. Just thinking though, how does one cut out (as in stall) an Automatic transmission Diesel?!

From what I've seen most people with autos who have had this happen seem to try and cut off the air supply to the engine by blocking the air intake. But I wouldn't be too keen on getting that close to an over revving engine.

This web page has a section titled "shutting off the air", and it claims that many Tdi engines have an electric solenoid butterfly valve which is setup to close the air intake once the key is switched off. George Dalton or one of the other mechanics on here should know if that would be sufficient or not to prevent this happening.

http://www.myturbodiesel.com/1000q/stop-runaway-diesel-engine-how-to.htm

RandomAccess

One other thing, the Landy in that second clip has its bonnet up and what looks like a bottle of engine oil sitting by the fender. Perhaps they overfilled the oil or had the engine running when they opened the oil filler or some other combination which helped to trigger the runaway.

Victor Meldrew

RandomAccess wrote: »

From what I've seen most people with autos who have had this happen seem to try and cut off the air supply to the engine by blocking the air intake. But I wouldn't be too keen on getting that close to an over revving engine.

(Honest question). Could you block the exhaust? (Assumes no exhaust leak)

Thinking orange over the tail pipe (soft, tough skin, readily avaialble)

jimgoose

Victor Meldrew wrote: »

(Honest question). Could you block the exhaust? (Assumes no exhaust leak)

Thinking orange over the tail pipe (soft, tough skin, readily avaialble)

That'll work on a mad, dieseling two-stroke bike, but probably won't get you far with a 2-litre turbodiesel.

Matt Simis

Victor Meldrew wrote: »

(Honest question). Could you block the exhaust? (Assumes no exhaust leak)

Thinking orange over the tail pipe (soft, tough skin, readily avaialble)

At high RPM, I think it would be blown off nearly instantly or even worse, at pressure seconds later! The idea is sound but likely you would need something fairly fit for purpose (something like a large cork piece that wont get pushed out easily). In my S8 I had one of those exhaust pipe trims (chrome surround) on the aftermarket exhaust. I had to use a lump hammer to put it on, very tight. It had a lip on the inside so by design impeded flow a little (for less noise).

One day on the M4 at high RPM the force of the exhaust gases were enough to blow the tip off, despite allowing 70% of the opening free flow! Something that blocked it 100%, when the engine is already at such RPM, would need to be inhumanly tight.

Cheensbo

Matt Simis wrote: »

At high RPM, I think it would be blown off nearly instantly or even worse, at pressure seconds later! The idea is sound but likely you would need something fairly fit for purpose (something like a large cork piece that wont get pushed out easily). In my S8 I had one of those exhaust pipe trims (chrome surround) on the aftermarket exhaust. I had to use a lump hammer to put it on, very tight. It had a lip on the inside so by design impeded flow a little (for less noise).

One day on the M4 at high RPM the force of the exhaust gases were enough to blow the tip off, despite allowing 70% of the opening free flow! Something that blocked it 100%, when the engine is already at such RPM, would need to be inhumanly tight.

So a potatoe then? :pac:

Ive heard of clutches being completely overpowered by a runaway diesel & basically removing all drivetrain out of the fray so no way to stop them other than co2 or running out of oil to burn..