A3 2.0 tdi sport turbo failure

[neil w]

About 2 1/2 years ago we bought a low mileage (40,000 ) A3 tdi sport with the 2.0 BKD engine , full Audi service history .

About 13 months later at 44,700 it suffered catastrophic turbo failure with the compressor shaft snapping and it dumping half of its oil into the exhaust. cut a long story short there was no engine damage so a local well respected vw specialist carried out the repairs .

The turbo was replaced with a brand new boxed Garrett unit, new oil feed pipe, gaskets etc. the intercooler pipes and all the inlets checked and cleaned (there was no debris present) and the oil and filters changed.

I ran it for 300 miles then dropped the oil (it was clean with no debris) changed it for Quantum Longlife 3 and continued to use it.

At 50,000 miles it was serviced again , using a genuine filter and Quanum Longlife 3 oil.

Anyhow yesterday at 54,500 miles (oil had been checked the day before and was 2/3 way up the dipstick between the marks) and 17 months after the car was originally repaired the new turbo went bang in exactly the same manner , car has always been driven properly, never thrashed from cold and always allowed to tick over after a run to cool down the turbo .

Any ideas as to why the hell this has happened again, cannot believe it is lack of lubricationl as when it has failed it has dumped half its sump oil into the exhaust within a couple of seconds

[neil w]

Quick update, pulled the intercooler to inlet manifold pip and it is totally clean, a very fine oil mist but not soaked and oil and definitely no debris or small particles of aluminium etc.
Can only assume that the car has done exactly ths same as last time , ie snapped compressor shaft allowing oil to godown the exhaust,.
Stuck the car on vcds and turbo failed and lost boost at 2300 revs travelling at 55mph and I know I was in fourth so it wasn't being over revved and had travelled the previous 15 miles at a steady 60mph in 6th gear .

[Doctle Odd]

The turbo should have a 2 year guarantee if it came from Audi

[Crasher]

That is an extremely unusual failure for a Garrett turbo on a BKD once, never mind twice. Yes the KKK on the 1.9 8v does this and I have had one or two Garrett units on PQ34 platform cars do this such as the 150 ARL engine, but the BKD normally just suffers from hoot/whine and then over-boost shut down. From what you say I would suspect that the engine ECU has been remapped and the turbo is over speeding.

[zollaf]

yep, my thought exactly, a dodgy remap from someone who doesn't know much about remapping.

[neil w]

This car is standard so that isn't the problem and always run on good quality fuel, I spoke to the garage which carried out the work and they are contacting their supplier but is appears that the turbo as a new unit has a 2 year warranty so fingers crossed.

Wouldn't care but my old 1996 A4 1.9 tdi (afn engine) had 180,000 miles on its original turbo and is still going strong around the area with well over 200,000 miles on the clock.

I know there is a lot said about gently warming up a turbo and then allowing it to cool before turning it off (which we do on our own cars) yet at work before I retired we ran a fleet of 60 + transit turbo diesels for the last 20 years which were changed every 3 to 4 years with 150,000 miles on the clock. Being emergency service vehicles they ran 24 hours a day very often going from cold to maximum revs and then run that way for runs of up to 50 miles on the rev limiters , on arrival at the job they were switched off immediately with no cool down period.

Yet we had no reported cases of turbo failure (confirmed by speaking to a mate in our fleet management today) so why does it seem to be so common on newer (post 2000 ) vag vehicles ie pd engines onwards

[Crasher]

You don't need to warm up or "spoil and cool" a diesel turbo as they don't get hot enough. It would be interesting to know if the shaft shows signs of the bearings picking up.

[neil w]

The independent dealer who did the work has spoken to their supplier and confirmed that the new turbo does have a 2 year warranty so it is going in this week to get sorted, will get them to pull the intercooler and pipes (again) and see if the local Advanced Radiators can clean it if not I will stick on a new intercooler , just in case.

Had the exhaust off today and got the oil out of it (there wasn't much - last time there was about 2 pints ) but looking underneath there is lot of oil in the area of the turbo, the feed pipe which is new is secure and has no leaks and the turbo drain pipe is fine , as the oil is external I am beginning think it it the turbos seals that have let go. Last time when the shaft went there were no external leaks and the oil went straight into the exhaust

[neil w]

New turbo on car went down to have a look at the aftermath of the failure and it can only really be put down to a failure of the cast alloy housing. Plenty of oil around and it looks like the beaings were fine but when the casting has sheared and when it lost boost it looks like casing has hit the still driven impeller which has then exploded , (the bits of impeller pictured were still on the shaft but it was far from intact) , one of the bits has actually blasted a hole in the plastic undertray on its way to freedom.

All the pipes have been cleared and a good /uncontaminated used intercooler will be going on a if it can't be cleaned a used catalytic convertor of a cat bypass pipe

[zollaf]

only time i have seen one fail like that is on these cheap as hell copy turbo's from china.made to look like a garret, but nothing like a garret, but 1/5 the price.