4.0TT Turbo Failure Thread - S6 S7 RS7 A8 S8
 

There is a similar thread over on another forum but I wanted some insight here as to what is going on with folks who have the 4.0TT motors and if they are seeing turbo failure(s) due to the turbo oil inlet screen disaster - essentially oil starvation.
(Text below is taken from the other forum).

I wanted to create a more basic poll to find out how many owners of the 4.0TT have had to replace their turbos yet. It would be good to get a better grasp on just how many owners have had this issue or not. I've included model years of 13' - 17', marked with a "Yes" (blown turbos) or "No" (still original). Then below please post your model and year if not visible and appox what mileage they blew or what mileage you are currently at on the stockers still.

PLEASE POST YOUR MILEAGE! - It can be very helpful in knowing how long / short the lifespan has been on these turbos. Any other info you want to share as well that could be helpful. (Driving style, climate, tracking the car, oil change info, etc.)

This is all centered around this Audi TSB: https://testing-public.carmd.com/Tsb...110859/A171566

https://cimg1.ibsrv.net/gimg/www.aud...d6bb5eb95c.jpg

2014 A8 that I picked up in May of 17 with just short of 19k on the odometer.
I have done regular oil changes sooner than 10k (maybe average out to 7k).
No turbo issues to speak of and the car has over 56k now and no evidence the screen was ever done before I took delivery of the vehicle.
The car was tuned with APR Stage 1 software fairly soon after getting it, run on 100 octane a bunch of times, and been down the drag strip in 1/4 mile passes.
Unfortunately the reports of failures has me spooked. On Friday I locked down a 2017 Q7. I should be picking it up later this week. Happy to be staying in the Audi Family!

2015 with 34k still original.

a lil confused
 

This link (https://testing-public.carmd.com/Tsb...110859/A171566) talks about the PCV (aka oil seperator) and not the blown turbos...

My seperator failed at 51K miles. Turbo is fine still.

2013 A8L 4.0T

Sorry about that. If someone can provide the link to the TSB for the oil feed screen I can edit my original post...

2013 with 168k miles
 

2013 60k miles
 

Mine just blew last Saturday. Was driving to Grand Rapids and once I pulled off the highway my car just completely shut down. Couldn’t move the steering wheel, brake pedal was locked up, couldn’t get it in any other gear besides park and engine wouldn’t start back up. There wasn’t any shaking, or any warning signs before this happened. Still at the dealership.

What did new cores run you?
And what was labor? Or did you DIY?

Hoping for the best. Have you considered calling AOA and mentioning the "known issue"?

2013 60k miles
 

I love the car but this is the reason I am going with a 2017 Q7... and more space for more toys.

I'm guessing you DIY. I would assume more hours of labor through a shop? Probably something like ~$750 in labor I would guess.

So those were not genuine Audi parts?

I am spooked as well with all these turbo failure reports. I just purchased my S8 at end of September last year. 75,000 miles on it. Runs perfect other than the 1k/3k vibration issue due to downpipes and I also think I need my sway bars done (another known issue with this car). I am not going to wait for my turbos to fail. I am lining up to have the oil separator, oil screen, and check valve all replaced as preventative maintenance. Until that is done I am driving the car sparingly. I will be changing oil at least every 5,000 miles after that. I just did an engine flush with liquimoly so I am concerned that may have loosened carbon particles and further blocked the restrictive screen. I will report back with pictures after the work is done. I am interested to see condition of turbos and oil screen. The factory oil screen apparently has been updated to allow more flow. Hopefully that fixes the issue.

My car is a 3.0T but a co-worker has a 2013 4.0T and received a letter from Audi extending the warranty on the turbochargers.

I hear you on this... Perhaps if I did more research before I purchased the car, I may not have gone through with it. However, I saw her and fell in love immediately. Then like a drunken night in Vegas, I woke up badly hung over and she was in my garage. Now that the honeymoon is over, I am finding she has some serious issues that need to be addressed. I guess that's the good thing about cars, you can fix the issues whereas with people, we are pretty much who we are. After those issues are fixed, I am hoping we will have a long happy life together. :)

First I have heard of this... Has anyone else gotten this letter???

These motors are incredible and one of the big reasons to go with the 4.0TT was driving a 2016 S6 that my dad had; plus the build quality of the interior is second to none. Unless going with a total bespoke handmade car (bently, aston martin, rolls, etc.) One thing I always found annoying was the lack of technicians that could work on this level of vehicles. One or two per dealership and it felt like the smallest thing was always a production. But that's what you get for daily driving a $112k extended wheelbase limo...

Same here, more details on this would help a lot of folks. See if you can get a pic of any paperwork your coworker has...

My mistake. Sorry to get anyone's hopes up. They also have an Allroad in the familly and it was related to the 2.0T.

I would say absolutely. Same engine base with same problem reported. Also, more production on those cars and thus more experience/results to harvest.

I posted in the C7 S6 S7 RS7 sections, hope I hit them all. I linked this thread in my first post, hopefully we get some more input from the other 4.0TT folks!

From the other Forum posting, most recent I have seen is version 4, shown below.


https://cimg9.ibsrv.net/gimg/www.aud...91ee2a87d3.jpg

https://cimg9.ibsrv.net/gimg/www.aud...0113fd1cf3.jpg

https://cimg1.ibsrv.net/gimg/www.aud...cfbafb6e63.jpg


https://cimg4.ibsrv.net/gimg/www.aud...02cc60f961.jpg

Try this search term for the PDF file:

21 Engine difficult to start, turbocharger damaged, V8 4.0TFSI

This link: http://www.revbase.com/BBBMotor/TSb/...dPdf?id=205336

There are 44 Audi 4.0TT failed turbos on another forum.

Here is the Silly Rabbit Motorsports gasket sets, Turbo cartridge aand turbo upgrades....4.0TFSI RS7 CHRA Turbo Upgrade

"Factory size and hybrid RS6 RS7 S8 Turbo core upgrade to take your S6 S7 A8 to stage 3 power or simply replace your blown RS6 RS7 S8 chra's. For more power than RS7 OEM turbos, you need to look at the ball bearing upgrade solution listed here http://sillyrabbitmotorsport.com/tur...turbo-upgrade.

2013 S8 with 77K miles, APR Stage 1 and 2, and I drive it like I stole it, hard. Probably just a matter of time on the turbos. I'm already looking into silly rabbit and others.

So this thread (and others like it) have been giving me heartburn for some time, so I figured I better chime in. I purchased my 2013 S8 with 48,000 miles on it in October of 2017. <knock wood>It now has about 58,000 trouble free miles <\knock wood>

The previous owner (or more likely the dealer that took it back in on lease expiration) did the turbo coolant line TSB on mine just before I purchased it. Unfortunately, that TSB doesn't cover the upgraded oil strainer or check value.

So here's my question...

If the 'Optimized' oil strainer ($15) and check valve ($50) fixes the problem, why wouldn't AOA just issue a recall? They should be able to upgrade every single 4.0 TFSI in USA for less than the cost of one new D5. Its certainly a hell of a lot less money than a set of blown turbos for us faithful customers left twisting in the wind. Does it make sense to just do this at my next service visit?

Has anyone done the Silly Rabbit upgrade? Is this a reasonable prophylactic to undertake? And my big concern would be, why wouldn't the upgraded turbo's fail just like the factory turbos are prone to do? And does Silly Rabbit have an ECU tune that works with the upgraded turbo's? Does APR tune work well with the upgraded turbo's?

You see honey, I had no choice but to get the upgraded turbos for my S8 and an APR stage 1 tune. The Audi turbo's blow up and cost $10k to replace. Silly Rabbit has better turbo's for only $2k. It's a smart and prudent investment. If we don't get in front of this now and fix it before it breaks... oh well, I suppose the kids can always put themselves through college. ;)

Lastly I'll just say that I'm not going to throw in the towel on this car - it seems we have some options. Luckily with turbo's on the top of the engine and they appear to be somewhat easy to service. And service, with what sounds like, potentially better performing aftermarket parts. So even if they do go, a fix can be had for roughly $2k-3k. That just doesn't seem that terrible to me - certainly not worth a case of heartburn. I get it and I'm with you: a $10k repair bill keeps me awake at night. $3k I can live with - maybe even jump in and do it as preventative maintenance. But I'll have to learn more about what the aftermarket options are before making my decision.

Aftermarket/upgrades sourcing
 

Just got off the phone with those guys. Very knowledgeable. As we know the RS7 turbo is the S8 turbo. They have those out of the box ready to go for replacement. Probably the easiest route(3k). No change or upgrade to performance. They offer 2 other types that are ball busters putting them at 825 whp. But you need all their other components to get there. Intake, fuel system, hpfp, custom tune beyond APR's stage 2. Spending closer to 12k. They make them in house. Said the sold over 200 pairs last year and had 2 failures. As the earlier post stated, 3k is not a big deal in the big picture. No need to think your out of the car. Good to know there is a 3k solution to these when they **** the bed. And a monster out there if I wanna spend the $.

My feelings exactly. At 34k with 9 months left of CPO I can still get nearly all my $ out of the car I've put in to it, so I'm The Clash: Should I Stay Or Should I Go?

2013 audi S8

60000km and both turbos failed. oil filter screen I believe was the issue. Has anyone replaced or even more so REMOVED them completely? Also curious if anyone has replaced their S8 turbos with RS7 turbos??? I'm in the process of getting mine rebuilt or popping on RS7 rebuilt turbos but not sure how that will affect my unitronic tune.

If you look up the part numbers you will find almost the same part number for the S8 & RS7 turbos.

2013/2014 S8
Part Number: 079145722A turbocharger 4.0 LITER, w/S8 Right
Part Number: 079145721A turbocharger 4.0 LITER, w/S8 Left

2014 RS7
Part Number: 079145722B turbocharger 4.0 LITER, w/RS7 Right
Part Number: 079145721B turbocharger 4.0 LITER, w/RS7 Left

I would not run without the oil screen, but the new one (rev G) will not clog as easily.

Also more info:

https://cimg5.ibsrv.net/gimg/www.aud...20dfd02f2c.jpg

From Reference: Königstedt, J.; Aßmann, M.; Brinkmann, C.; Eiser, A.; Grob, A.; Jablonski, J.; Müller, R.: The new 4.0l V8 TFSI engines from Audi. 33rd Vienna International Engine Symposium, 2012

The S8 & RS7 have a larger 67mm main bearing journal than the S6/S7/A8, 65mm.
The material used for the V8 TFSI is C38 mod. with 65 mm main bearing diameter;
for the higher-powered variant (S8/RS7) the material is 42CrMoS4 with 67 mm main bearing diameter.

The static compression ratio of the S8 & RS7 are lower, 9.3 : 1, compared to the S6/S7/A8 of 10.1 : 1,
so different pistons.

Engine Block (infers that the S8 & RS7 blocks have extra T6 heat treating)
The engine block is made as a homogeneous low-pressure gravity die-cast block
from the hypereutectic aluminium-silicon alloy ALSi17Cu4Mg. Owing to the increased specific power output
and the associated increase in thermal and mechanical loading, the 382 kW variant is additionally heat-treated
by the T6 process.

The cylinder heads for all performance versions of the engine are laid out identically.
The only difference consists in different valve timing (lift event lengths for the camshafts)
in the engine variants with more than 420 hp (309 kW).

The cooling systems for the A8 and S8 are identical with the exception of the ATF heating/cooing

Airflow in the S6, S7, and A8
All engines in the C7 series and the A8 with the 420hp (309 kW) engine variant have
their air intake on one side. The intake air is taken through only one air filter module.

The Audi S8 has a dual-branch air intake. Each cylinder bank has its own air filter
module on the respective side of the vehicle.

All engines in the S6, S7 and A8 with the 420 hp (309 kW) engine variant have
their air intake on one side. The intake air is taken through only one air filter module.

On engines with a power output of 520 hp (382 kW) the compressor wheels are
larger, providing for the greater air requirements of the engine.

An additional oil cooler is installed on the S8 version of the engine. It is an air-to-oil cooler
mounted at the front of the vehicle. Oil does not flow through this cooler continuously.
Flow through the additional oil cooler is regulated by a thermostat. The thermostat is located
in the oil passage of the upper part of the oil pan and opens at an oil temperature of 230 F (110°C).

The only difference in the turbocharger module between the 309 and 382 kW engines (S8/RS7) is that the
variant with higher power output has a larger compressor wheel diameter, and so the machining
in the compressor housing is adapted accordingly.

2013 A8L
 

The only difference in the turbocharger module between the 309 and 382 kW engines (S8/RS7) is that the
variant with higher power output has a larger compressor wheel diameter, and so the machining
in the compressor housing is adapted accordingly.[/QUOTE]
Good work M444.

This is exactly what I would like to know also. And what does the check valve do (or not do) that is supposedly the cause of the turbo failures?

otherwise when you shut the car off the oil would drain with gravity's help back into the oil pan and the bearings would start up (essentially) dry until oil from the sump was pumped back up to the turbos...

Well my car is currently at the dealer. 2013 S6 with 63000 miles on it. All services completed by the dealer and at recommended intervals. Both turbos are blown. Received a quote of about 13K to repair the turbos and the breather assembly repair, Im assuming thats the oil separator issue. I have contacted Audi of America to see if they can do anything. If they cant then I have to see which route to go.