What are the consequences of a diesel turbo failure

[Salty seadog]

Black smoke probably means soot, and the soot will most likely be from unburnt fuel rather than engine oil that has leaked past seals and got into the combustion process (leaked engine oil will generally give clouds of greyish smoke). As yours is an older vehicle, it may well not have a particulate filter, and I'd always thought that older diesel vehicles were well known for producing quite a bit of soot in the delay between the fuel being increased and the turbo spinning up to give the extra air for combustion. Also, as others have suggested, a blocked air filter could cause excessive soot for the exact same reason that there is too much fuel and not enough air. Yet another explanation is that some part of the injection system is faulty or wrongly adjusted, leading to over fueling. First thing I would do is replace the air filter, and see if there is any improvement, as it is a relatively quick, cheap and easy job.

Thanks, another great reply and readers my mind somewhat. It does I believe have a dpf fitted.

 

[screenman]

Thanks, another great reply and readers my mind somewhat. It does I believe have a dpf fitted.

I doubt that it has a DPF at that age.

 

[Colin_P]

If you can...

Do an interim oil and oil filter change on the car yourself between services. It is an easy thing to learn and do and will cost you less than £30 (or less) and a few hours on a Saturday morning. It is the single most important and best thing you can do for any turbo diesel engined car and will pay dividends on the life span of your car, turbo included.

For example;

If you get it serviced every 10,000 miles, do your own oil and oil filter change in the middle at 5,000

or

If you get it serviced once a year in say December, do your own oil and oil filter change every June.


Furthermore, even older diesel cars, like yours, will have some form of emission control system on them. For that age age it will likely be an EGR (exhaust emission recirculation) system. These by their very nature will get clogged with soot and gunge restricting the airflow into the engine. It'd be well worth investigating on how to clean it (again a couple of hours work for you) or get your garage to do it. It doesn't need doing at every service but could make a huge difference.

Here is a clogged EGR valve, that gunk needs to be gently scraped and washed (with solvents) out of there. Doing the Italian tune up on a regular basis helps to blow some of that out but will not prevent it. If any car is as bad as that pic, no amount IT'ing will help, it needs to come off and be cleaned.

 

[Yellow Saddle]

If you can...

Do an interim oil and oil filter change on the car yourself between services. It is an easy thing to learn and do and will cost you less than £30 (or less) and a few hours on a Saturday morning. It is the single most important and best thing you can do for any turbo diesel engined car and will pay dividends on the life span of your car, turbo included.

For example;

If you get it serviced every 10,000 miles, do your own oil and oil filter change in the middle at 5,000

or

If you get it serviced once a year in say December, do your own oil and oil filter change every June.


Furthermore, even older diesel cars, like yours, will have some form of emission control system on them. For that age age it will likely be an EGR (exhaust emission recirculation) system. These by their very nature will get clogged with soot and gunge restricting the airflow into the engine. It'd be well worth investigating on how to clean it (again a couple of hours work for you) or get your garage to do it. It doesn't need doing at every service but could make a huge difference.

Here is a clogged EGR valve, that gunk needs to be gently scraped and washed (with solvents) out of there. Doing the Italian tune up on a regular basis helps to blow some of that out but will not prevent it. If any car is as bad as that pic, no amount IT'ing will help, it needs to come off and be cleaned.

What is an EGR Valve?

 

[Colin_P]

EGR valve = Exhaust Gas Recirculation valve.

It partly re-directs hot exhaust gas back into the inlet so it gets re-burnt. The main purpose is to reduce Nitrogen Oxide / Dioxide emissions. Even older diesels, like the OP's had these but not all.

 

[screenman]

Must admit I stick to 20,000 mile oil changes. I do change my cars around 180 too 200,000 miles though.

 

[Yellow Saddle]

EGR valve = Exhaust Gas Recirculation valve.

It partly re-directs hot exhaust gas back into the inlet so it gets re-burnt. The main purpose is to reduce Nitrogen Oxide / Dioxide emissions. Even older diesels, like the OP's had these but not all.

Thanks. What can I expect to find in my Golf TDI's EGR at 100K miles then? Should I take a peek?

 

[raleighnut]

What they probably mean is that replacing the turbine unit is so expensive it will be not economically viable to do so (cost more than the car is worth)

 

[Colin_P]

Thanks. What can I expect to find in my Golf TDI's EGR at 100K miles then? Should I take a peek?

You may have a moderate build up of oil sooty gunge. It is always worth having a look.

What age Golf is it?

 

[Bazzer]

Thanks, that had put my mind at ease no end. Full service history and always replaced parts, timing belts etc at the correct time. Next service in a couple of months. Only smoked under hard acceleration (black but not thick). A few people have told me my millage (125 thousand) is about the lifespan of a turbo.

I've had the car since it was 18 months old so know its history as it was used by the Toyota dealership manager for that time.

My Golf TDI has almost 160k on the clock and (touch wood) is still as good as when I bought it over a 100k miles ago.
Still a youngster compared to my previous (petrol) Golf with which I enjoyed almost 250k of miles before it started to burn oil.

 

[Yellow Saddle]

You may have a moderate build up of oil sooty gunge. It is always worth having a look.

What age Golf is it?

2010 TDI with DPF and BlueStuff

 

[Colin_P]

2010 TDI with DPF and BlueStuff

I don't know a great deal about those other than the emission control systems are fragile. But it could be sooty in there!

We (Me and the Wife) still drive ancient (early 2000's) VW TDI's which go on and on and on and on. I've put off buying anything newer as I don't think they are robust enough.

 

[Yellow Saddle]

I don't know a great deal about those other than the emission control systems are fragile. But it could be sooty in there!

We (Me and the Wife) still drive ancient (early 2000's) VW TDI's which go on and on and on and on. I've put off buying anything newer as I don't think they are robust enough.

Thanks

 

[PpPete]

What often happens is that when a turbo fails, it is the oil seals on the rotor shaft that let go. This allows engine oil to be drawn into the inlet tract and the engine will feed off its own oil. As this is an unmetered fuel supply the engine will 'run away' revving out at maximum revs until the oil supply is exhausted at which point the engine will seize.

A very frightening thing to witness as there is no way of stopping it. You might be lucky enough to have the presence of mind to stall the engine though, the key will have no effect once this starts.

But that is an extreme case and is the one that will cause a written off engine.

Usually you will get plenty of warning, noise (chatter), smoke and an engine that seems to use a lot of oil between top ups. You do check your oil every week?

[edit] a good video example of diesel engine runaways...

View: https://youtu.be/xmIfjmvXp0I

I had this happen on a Citroen C8 - as Coling says, rather frightening, because turning the key don't turn off the engine.
Not knowing what was happening I didn't know to stall the engine.

Result: write-off. Not worth new engine + turbo.

 

[Salty seadog]

Some excellent replies, I have an annual service with oil change and filters changed. Only do about 7-10 thousand miles a year so it should be in reasonable health. I can feel no difference in the cars power and it feels tight as a drum with power delivery and acceleration.
Will consult local and trusted garage who do all my work and get them to take a peek for build ups inside as mentioned..