TDI90 turbo failure - fix or don't fix? - undecided.

RAB said:
Doesn't work for a VNT turbo. The only solution is to dismantle and clean.

In my experience, driving hard is unnecessary. Getting the turbo up to normal temperature for most journeys is more important.

RAB
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Erm, RAB my experience shows otherwise. My TDi 90 was bought in Oct-2009 with 47,000 miles on the clock, and a known issue of "limp mode" after the car had been used on school runs by the second owner. Limp mode tended to occur on long drags on either dual carriageways or motorways. It didn't bother me that much.

Ironically the issue became intolerably bad driving over the M62 to the inaugural A2OC Yorkshire meet at Saltaire, 22-May-2016. I thought it was new turbo time (the car would have had about 128,000 miles on the clock). My service garage (Audi Doctor, Stockport) advised me:
  • to use premium diesel, and
  • to "drive the car like you have stolen it!".
One journey I occasionally make includes a long, gentle climb on a national speed limit dual carriageway: with my foot to the floor in third gear, the car achieves 70mph; this climb lasts four or five minutes. This is followed by a 12% hill (national speed limit single carriageway): with my foot to the floor in second gear, the car achieves 50mph; this climb lasts two or three minutes.

The first couple of times driving like this the car would make it along the dual carriageway, then go into limp mode on the 12% climb. After a few times it was able to do both climbs: (touch wood) the car no longer goes into "limp mode" under any driving conditions.

Several months ago I ditched the expensive premium diesel (Shell V-Power). I am now running Sainsbury/Asda/Morrissons cheap as chips diesel. I continue to rev into the red line when I am in the mood and conditions permit. (I would only consider doing this when the temperature has reached 90ºC). The car now has 150,000 miles on the clock.

All the best, Andrew
 
andrewparkeruk said:
  • to "drive the car like you have stolen it!".
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That's the only way to drive a car providing it is fully and correctly maintained.

Edit: just read the comment from RAB, not sure we are saying the same thing but warm it up before you really drive it and never switch it off cool.
 
rosscanning said:
Any update Kennedy?
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Hi folks, yes I do have an update…

The car was trailered to the friendly chaps at WOM at the end of last month with the intention to have it repaired as I had come to the realisation that I would struggle to find a similar car and then add all the upgrades again like I have done to this car. I had also realised that after several weeks of the car going nowhere I was just not going to find the time to investigate the work needed myself.

I had a fairly clear idea of what the costs were depending on the severity of turbo failure, the cheapest option being a clean and refurb of the existing unit if it was in serviceable condition, the more expensive option being a new replacement if the turbo was beyond repair…

Rob and Marcus didn’t mess about, the turbo was off the car by the next day and official diagnosis soon came in; unfortunately it was the latter (more expensive) option!!… the turbo shaft had snapped exhaust side and we later found out from the turbo specialists that this had resulted in damage to the turbo housing leaving the unit beyond repair. Also of note was that the turbo was badly coked up (no surprises there), probably the reason so much strain was placed on the shaft. I’ll try and get a picture of the damage to post up.

At this stage I am already in far enough that the car is going to leave me with a decent sized bill so rather than have the car delivered back to me in it’s slightly dismantled, non running state (at more cost) I’ve given the green light to WOM on the new turbo supply and fit along with any ancillary parts and associated work… which I am nervous about for all the reasons mentioned in my first post, mainly that this is the second time this work is being completed on this car!

But I’m remaining optimistic, it is a good car and I’ll be happy to get it back assuming all the work goes as planned. The turbo will be delivered to WOM in the next day or two if it’s not there already and then I assume it’ll be rebuilt in the next week. Fingers crossed it goes okay.…

Other essential work as I understand it is all the obvious stuff, all new gaskets and seals, oil and filter change, new oil feed/return pipes and decontamination of anything else being refitted. In addition the EGR is getting a thorough clean out as it makes sense to do that while access is easy and pipes are disconnected.

Following that I am considering having the EGR functionality disabled so no exhaust gasses are recycled back through my engine, and I may go as far as investigating the removal of the actual EGR valve within the housing, much like the work completed on Timmus’ TDI120 engine build... we'll see.

Kennedy.
 
So just picking up on this thread... any updates on the success of the work carried out?

Also as a general question is it worth doing any kind of preventative cleaning on a vnt or not and what options are there without big expense? Just becoming ever aware that my car is now into 133k miles with original turbo as far at I'm aware.
 
johnyfartbox said:
An Italian tune up works wonders for any Diesel that only does short journeys, try it.
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Italian Tune won't repair it / clean it but I agree it will stop it from happening in the first place. The vanes get stuck because of carbon build up, same with DPF's, car engines are designed to work up to their redline and be used up to the redline occasionally. If the car is never revved above 50% of max revs then it will get asthmatic just as if we never exercise we seize up (which reminds me...).

Problem with German cars is they are designed to travel at maximum speed every now and again, autobahns etc.

A workshop I frequented north of Mansfield a while ago has a magical liquid which they squirted into the intake manifold that would cure these kinds of problems. The liquid is VERY expensive as its designed to clean carbon deposits off the turbine blades of jet engines. It soaks into the carbon, changing its molecular composition then as the temperature rises the carbon becomes brittle and shatters off. They swore by it.

Worth a try: https://reviveturbocleaner.com
 
cheechy said:
...is it worth doing any kind of preventative cleaning on a vnt or not and what options are there without big expense?
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My 90 has done 170,000 miles and the turbo is fine. Car often used on motorways (70% of time, 70 mile journeys typically). See above for cleaner.
 
My 90 has just hit 170000 and I’ve just had the remap done it’s great. Hoping the more spirited driving kicks off carbon. Nothing major has failed yet!


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Edwrai said:
My 90 has just hit 170000 and I’ve just had the remap done it’s great. Hoping the more spirited driving kicks off carbon. Nothing major has failed yet!


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Drive or like your stole it but only when up to 90 deg


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