Touareg 2007 V6 TDI 190,000 miles

[Wilki99]

Big troubles
Suspected turbo oil seal blown.
Started car (after a 50 mile journey and a 15 minute rest) and traveled approximately 1 mile only to feel the car judder and a large clouds of black smoke from the exhaust.
The car was hunting badly and seemed to be in limp mode.
Switched engine off and back on again and got the same symptoms.
I unscrewed and pulled off the turbo pressure hose from the inter-cooler to the inlet manifolds and it was very wet with oil.
I pulled the dipstick and it showed no oil.
I am in the process of removing the turbo at the moment and while removing the turbo pressure hose to the inter coolers noticed that the inter-cooler pipes are full of oil (there must be litres of oil in there).
Can anybody give me an explanation of what has caused this.
I would have thought that a blown oil seal on a turbo would have been a little less drastic in that the car would have smoked a little at first giving me tell-tale signs that the turbo was failing, rather than a catastrophic dumping of the entire contents of my engine oil into my inter-cooler pipes and subsequently back into the engine intake system.

The only issue VCDS showed before this was P0401 Insufficient Flow, which I should have taken as the car was burning more oil than it should and the EGR Valve and Cooler was getting blocked.
Can a blocked EGR valve cause this sort of issue?

Any help would be appreciated.

[Crasher]

A turbo does not actually have a shaft seal in the traditional way, they use a metal ring on the shaft called a piston ring for some odd reason. If you have the turbo rebuilt (Midland Turbo are exceptionally good) they will tell you what they think caused it after stripping it down, we always follow
their advice and the usual reason is oil starvation. Yours could be Borgwarner or Garrett The Turbocharger Oil and Gas Sealing System - Garrett Motion (https://www.garrettmotion.com/news/newsroom/article/the-turbocharger-oil-and-gas-sealing-system/)

[Wilki99]

OK, Thanks Crasher
I can now see that the shaft is broken and parts of the compressor are broken off and the whole compressor impeller is loose.
The fact that i have lost a considerable amount of engine oil through the turbo suggests to me that it was not a lubrication issue but i may be wrong.
I change my engine oil every 10,000 miles or less.
Maybe it was an age/mileage related issue. I don't know what the average life expectancy of a turbocharger is.
Thanks for your reply anyway.

[Crasher]

The turbo is relatively easy to remove so send it to a specialist and whilst it is away, you have a lot of cleaning to do; you are going to have to remove the entire charge air system and flush it out, hoping no fragments of compressor wheel have got into the engine. At least the oil didn’t cause a runaway which can happen when engine oil sprays into the intake. If the oil goes down the exhaust from the turbine side it means having the DPF professionally cleaned and getting the oil out of the silencers is nearly impossible, we drill a 3mm hole at low points to start with and see how much the smoking is.

[Gnits]

Can anybody give me an explanation of what has caused this.
Oil got past the turbo seals and leaked into charge air hose.



I would have thought that a blown oil seal on a turbo would have been a little less drastic
Turbo seals usually don't get "blown", they just start to seep. That being said, because of how the charge air system is built, a lot of oil can pool in the charge air hose and in the intercooler over time.


in that the car would have smoked a little at first giving me tell-tale signs that the turbo was failing, rather than a catastrophic dumping of the entire contents of my engine oil into my inter-cooler pipes and subsequently back into the engine intake system.
You most likely had this going on for a while, ie. the oil has been pooling in the charge air hose and in the intercooler. Then once it reached a certain point of level/saturation, or when you pushed the pedal heavier than usually, it all got caught up from there and catapulted with and by the charge air right into your intake manifold and into the cylinders. If it was a large enough mass that got in there at once, you might even have damage to your pistons or valves. See hydrolocking!


The only issue VCDS showed before this was P0401 Insufficient Flow, which I should have taken as the car was burning more oil than it should and the EGR Valve and Cooler was getting blocked.
Can a blocked EGR valve cause this sort of issue?
No. It's the other way round: once you have oil seeping into the charge air hose and into the intake manifold, the soot arriving there in/with the recirculated exhaust gas gets stuck in the oil, and creates a greasy gunk, that won't move and will block the EGR valve and also restrict the intake diameter. Which in turn can cause an insufficient flow fault.

[Gnits]

OK, Thanks Crasher
I can now see that the shaft is broken and parts of the compressor are broken off and the whole compressor impeller is loose.
The fact that i have lost a considerable amount of engine oil through the turbo suggests to me that it was not a lubrication issue but i may be wrong.
I change my engine oil every 10,000 miles or less.
Maybe it was an age/mileage related issue. I don't know what the average life expectancy of a turbocharger is.
Thanks for your reply anyway.
Nothing lasts forever, so, turbos don't either. But they should be good for at least 100.000-150.000 miles, and even then not fail catastrophically. But several things can shorten their lifespan dramatically or cause catastrophic failure. Most problematic of these is shutting off the engine immediately after you've arrived your destination. With a turbocharged engine you should never do that, because if you do, the turbo might still be very hot, and by shutting off the engine you make it impossible for the oil or the coolant to cool it down. So, when you shut off the engine, the turbo will literally burn the oil that's stuck in it or close to it onto the supply channel walls, and it will get stuck there as carbon deposits. Which of course is not a very good lubricator and also restricts the oil flow path and hinders the flow of the remaining oil.

Modern engines might have an auxiliary electronic pump which can keep the oil or the coolant circulating for a while even after the engine has been shut off, but those at best only mitigate the problem. Generally you should let the engine idle for 15-20 seconds after you've come to a halt, but before shutting it off, which should be enough to cool the turbo down to a temperature where it won't burn the oil stuck in it.

[Wilki99]

Thanks again Crasher, most helpful.

[Wilki99]

Nothing lasts forever, so, turbos don't either. But they should be good for at least 100.000-150.000 miles, and even then not fail catastrophically. But several things can shorten their lifespan dramatically or cause catastrophic failure. Most problematic of these is shutting off the engine immediately after you've arrived your destination. With a turbocharged engine you should never do that, because if you do, the turbo might still be very hot, and by shutting off the engine you make it impossible for the oil or the coolant to cool it down. So, when you shut off the engine, the turbo will literally burn the oil that's stuck in it or close to it onto the supply channel walls, and it will get stuck there as carbon deposits. Which of course is not a very good lubricator and also restricts the oil flow path and hinders the flow of the remaining oil.

Modern engines might have an auxiliary electronic pump which can keep the oil or the coolant circulating for a while even after the engine has been shut off, but those at best only mitigate the problem. Generally you should let the engine idle for 15-20 seconds after you've come to a halt, but before shutting it off, which should be enough to cool the turbo down to a temperature where it won't burn the oil stuck in it.

Thanks Gnits
I'm now in the process of a full clean down and removing Inter-cooler radiators.
De-greaser and pressure washer.