TDI Turbo Failure - spend $2000+ or find another solution.

[moreboost]

So......lets keep this in perspective.

We had a weird sounding turbo, yes a siren sounded the best description.... the previous owner admitted that there had been boost related warnings diagnosed by a VW specialist......

Any number of posts on our web search confirmed that a 'weird siren noise' often equated to seized vanes.....

The hot side of the turbo doesn't contain any aluminium.....

We ran a PVC dump and exhaust until there was NO further residue exiting the turbo...

I think the job was done without any damage to the car and it is running perfectly.....As I said in my second post we went to a lot of trouble to avoid doing damage. I wouldn't dream of using NaOH if the turbo wasn't significantly lower then the cylinder head ports. We timed the flow of foam into the turbo after working out flow rate and rough volume of turbo.

Thanks Gavin for the Link, we were about to head down that path before we came up with the Mr Muscle solution.

We gave our fix a try, if it didn't work we would have been pulling the turbo next and giving it a manual clean.
Will keep you posted if there are any further issues.

[gldgti]

Yeah good luck to ya - I'm just saying you can actually diagnose it with VCDS and a bit of testing rather than going on what some internet posts/youtube videos say.

You might have saved yourself the hassle of what you've already done.

My advice about rebuilding is only for if you need to end up doing it - not once did I say thats what was wrong with the car. I certianly wouldnt recommend pulling the turbo before you've done some proper diagnostics, unless you are just loving spending time under the car.

If someone can explain in engineering terms how siezed vanes will cause a siren sound, I'll give you $1000.

(The only thing remotely close might be severe turbo overspeed due to the vanes being closed and this would cause crazy boost.)

[moreboost]

Our problem is that there are no VW specialists in town and those in Perth are at least 425 kms away.
A VW 'dealer' opened here last year, same company as the Holden dealer and they do Jeep, Chrysler etc as well. Don't seem to keep service parts even......
So we went looking for a solution with the resources we had.

Post Mr Muscle the noise is different. Before the turbo seemed to spool up momentarily after you released the throttle and seemed slow to spin down,

something like this ( video is no load though)

https://www.youtube.com/watch?v=cc4ykrnn_3c

once the vanes were free (could physically feel the difference on the actuator) it was immediately obvious that the turbo slowed faster (vanes opening fully). Now sounds like any wastegated turbo....

[brad]

I thought those old fashioned air raid sirens were fixed vanes?

I'd assume all you need is the right angle & enough speed. Get on the right harmonic & it would howl like a coyote.

[benough]

That would be a hilarious trick, if you could position a VNT's vane to that point and make it howl on them. hahaha

[brad]

For anyone needing photos to understand what the OP did (it always helps me)

The Mr Muscle VNT Turbo Treatment - thought we needed a guide of sorts - General Guides - BRISKODA.net - The Skoda Forum and Community

initially it's for the 1.9tdi but eventually somebody deals with the 2.0L

[gldgti]

Your info about the actuator is a critical bit that was missing in your story for me. Sounds like you are on the right track.

brad, those old air raid sirens use compressed air fired out of hornpipes with a flow interruptor to cause pulses in the airflow coming out of the horns.

I have heard overspeeding VNT's - Its not the kind of noise you might expect from your TDI, but its not nearly as air raid siren sounding as a turbo with an imbalance.

Anyway, hopefully for the OP's friend the car is fixed.

[brad]

rotating vane type. That's why they do the slow wind up (start low & go high) I believe. Like on Hogan's Heroes


Pulse type?

[moreboost]

We didn't use the EGR route to add Mr Muscle as it was a far more convoluted loop to feed the hose on a 2 litre.
By removing the dump pipe we could visually inspect the turbine and we wanted to ensure the foam reached the correct section where the variable vanes are.
I made a sheet metal cylinder that fitted neatly in the stepped turbo outlet and joined this to our PVC dump pipe.


Sent from my iPad using Tapatalk

[brad]

I think in that link I added, for the 2.0L they talk about removing the DP (as you did) then spraying in the Mr Muscle & holding it in with a rubber glove over the turbo outlet for the 2hr soak time. They seem pretty keen on using a plastic hose as a delivery mechanism.