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Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Paul Howd on July 15, 2010, 9:10 pm

Year of Manufacture *: 54 plate
Engine Size and Code *: 3.0 V6
( Optional ) Scanner Used: Vag-Com (Full)
( Optional) Fault Codes: none

Customer complains of intermittent occasional loss of power when hot.

Sometimes "Glow plug" light comes on when driving.

Not seen the fault myself. Nor are there any fault codes stored.

Audi has apparently suggested that it is a turbo fault (Sticking Variable vane mechanism I would imagine, which is credible though I am not yet ready to change a one grand component on the basis of an educated guess) and have quoted him a grand for a new turbo (which seems about right) and over a grand for fitting!

Now, "Autodata" suggests about 3 hrs for the job and although I have only given it a cursory examination it doesn't look, in principle, to be too bad a job but am I missing something?? Why would Audi be quoting so much to do the replacement??

If anybody has had experience of turbo faults and replacement on these and has any words of wisdom to offer (Even if it is just "Run Away") I would be grateful.

Paul

Re: Audi A8 3.0TDI (V6 CR Diesel) Turbo replacement

Posted by Darren Bamford <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5465' width='330' height='300' border=0 style='border:none;'> on July 16, 2010, 11:32 am, in reply to "Audi A8 3.0TDI (V6 CR Diesel) Turbo replacement"
Darren Bamford

Hi Paul

quote
"Why would Audi be quoting so much to do the replacement?? "

simple really , the dealership in question probable employs about 70 staff ,the building will be the size of a small Hospital,they will have sky TV playing on multi screen TV's , leather sofas, the toilets will have gold plated taps and the reception area will look more like a café with free flowing coffee ,muffins and bacon rolls . You will have more choice of newspapers and mags than W H smiths have in stock.

someone has to pay for this shit.

I would have thought there would be some error recorded for turbo boost control error.

VAG diesels normally monitor turbo boost very closely and normally the slightest problem is recorded and logged as a DTC...

HTH

Darren

Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Andrew Ruellan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5382' width='330' height='300' border=0 style='border:none;'> on July 16, 2010, 4:02 pm, in reply to "Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #"
Andrew Ruellan

Hello Paul,

Have you checked "all" control modules for faults?

Could be another system using the glow plug light.Earlier VAGs did this for brake light switch faults in the ABS system.

Regards

Andrew

Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Paul Gunstone <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5530' width='330' height='300' border=0 style='border:none;'> on July 17, 2010, 8:31 pm, in reply to "Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #"

Hi paul,
Your repair time is not too far from the mark. These take around 3 to 3.5 hours to remove & install. Usual exchange price for these turbos are usually in the region of £695 plus vat from your dealer. As Darren has said, dealers have massive overheads, hence massive quotes! I'm a little concerned as to the reason the dealer has come to the conclusion that the turbo is at fault as these do tend to store codes as soon as any boost pressure data varies from the norm. If you have access to a decent Diagnosis Platform, run the vehicle & actuate the N75 boost pressure control valve via the tool & observe the actuation linkage. You will soon see if the VVT is sticking or rough during actuation. If this appears to be ok, connect the tool to the vehicle & take for a test drive. Load the vehicle in 3rd or 4th gear and observe the boost specified & actual values in live data. For some reason, VAG's maximum permissible boost pressure before faulting out usually appears to be 2601 mb on most models. If this figure is acheived, these vehicles drop into limp mode and lose all boost control until the ignition is cycled off/on. From memory, your normal boost readings should give a maximum of around 2395 to 2495 mb. As Andrew has suggested, I would do a complete scan of all ECU's as well just to be sure there are no faults elsewhere causing the lamp to illuminate. Sorry for the longwinded reply,
HTH, Gunner.

Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Darren Bamford <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5465' width='330' height='300' border=0 style='border:none;'> on July 17, 2010, 10:44 pm, in reply to "Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #"
Darren Bamford

Hi Paul G

Quote "If you have access to a decent Diagnosis Platform, run the vehicle & actuate the N75 boost pressure control valve "

Paul H has not provided the engine code for this vehicle ,but i would think It will have a Electronic motor on the Turbo to control the VNT mechanism.

NO vacuum Control on the VNT (Variable nozzle turbo)

Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Paul Gunstone <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5530' width='330' height='300' border=0 style='border:none;'> on July 18, 2010, 10:19 am, in reply to "Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #"

OOOOPS, you are of course quite right Darren

Appologies Paul, I should have read the vehicle details closer & realised that you stated common rail. The repair times for the turbo stands, but as Darren has pointed out, the actuation of this turbo is going to be electronic making it a VNT type, in which case there will be no Vacuum or N75 solenoid control present. The actuation of the turbo (albeit electronic) & boost pressure scenarios should still stand as good methods of diagnosis though. If you do find that the turbo is infact faulty, then Audi are doing some good prices within their 'exchange programme' at the moment. Sorry for the misplaced info, I'll read more closely in future!
Gunner.

Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #

Posted by Milan Lazarevic on July 18, 2010, 6:17 pm, in reply to "Re: Audi A8 3.0TDI (V6 CR Diesel) - Turbo replacement #"
Message modified by board administrator July 20, 2010, 3:15 pm

Turbo's for these are just over 1k from the dealer, you will be lucky to get one less that £720.00 aftermarket for New Unit, there not the easiest of turbo's to fit on these, but i don't think you have a sticking turbo issue, i would have expected a boost code for over or under if the glow plug light is flashing. You can check on these systems what the specific, demand and actual (feed back) from the electronic actuator that will give you a good idea of whats happening, I would also do full vehicle scan and see what else is logged.

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