Long time lurker, new used 2018 S6 owner

[Mr.Creasy]

Last Wednesday I pulled the trigger on a clean one owner 2018 S6 in Mythos Black.

I have a few questions for the C7/7.5 veterans.

1. What are some common issues with this platform? I've heard that the PCV system can get clogged and cause premature turbo failure. Anything else I should be aware of? Is there a way to combat this problem to improve the longevity of the stock turbos?

2. What is the best diagnostic tool for this car. Should I go VAG-com or will an OBD11pro suffice? I would like to be able to read and clear fault codes, change the ride height of the air suspension, and figure out other cool things that aren't enabled in the factory settings. Also if I can do any service or repairs myself and would need to reprogram any settings, I would like to be able to do this via the diagnostic tool.

3. My last question. My S6 has the sport package and I have heard that the rear differential is finicky if the car is tuned or otherwise putting down more power. Is there any solution to this? I dont plan on doing anything crazy but was considering getting a JB4, Cold Air Intake, intercooler, and turbo-back in the future.


Thanks!

[Alabama]

Last Wednesday I pulled the trigger on a clean one owner 2018 S6 in Mythos Black.

I have a few questions for the C7/7.5 veterans.

1. What are some common issues with this platform? I've heard that the PCV system can get clogged and cause premature turbo failure. Anything else I should be aware of? Is there a way to combat this problem to improve the longevity of the stock turbos?

Check out AZ thread "Why should I not buy a 2013 S6?".


2. What is the best diagnostic tool for this car. Should I go VAG-com or will an OBD11pro suffice? I would like to be able to read and clear fault codes, change the ride height of the air suspension, and figure out other cool things that aren't enabled in the factory settings. Also if I can do any service or repairs myself and would need to reprogram any settings, I would like to be able to do this via the diagnostic tool.

Most folk seem to think VAG-com is superior (more options) but at a higher price.


3. My last question. My S6 has the sport package and I have heard that the rear differential is finicky if the car is tuned or otherwise putting down more power. Is there any solution to this? I dont plan on doing anything crazy but was considering getting a JB4, Cold Air Intake, intercooler, and turbo-back in the future.

I've seen more concerns expressed about the transmission than the differential when doing modifications that increase engine power (see #1 above), though not so much with just a Stage 1 increase.

[Mr.Creasy]

Thanks for the info. Do the sway bars on yours make a noticable difference on understeer? I used to own a GTI and as good as the s6 is it is porky and tends to understeer

[jrhgto]

Yeah I believe the 2 big issues are the Turbo oil screens and the Transmission Mechatronic issue.

It sounds like the updated oil screen was fitted to cars starting in 2017 so I believe the '17 and '18 model years are less of a concern for the turbos. The Mechatronic issue seems less common, but it is still a very expensive repair, and I am not sure if there is PM to avoid or delay that one. Motor mount issues are common across the C7 platform, and vary widely. I had mine replaced at 140K on my A6...The S6 mounts ( and pretty much everything else) are more expensive to replace.

[Alabama]

Thanks for the info. Do the sway bars on yours make a noticable difference on understeer? I used to own a GTI and as good as the s6 is it is porky and tends to understeer

"2015 Audi S6 H&R sway bars" is a great thread for information. I don't have objective data but I and others believe the car handles better. There are other brands besides H&R also discussed on other AZ threads.

[Audisthesia]

Thanks for the info. Do the sway bars on yours make a noticable difference on understeer? I used to own a GTI and as good as the s6 is it is porky and tends to understeer

Yes. When looking for sways, be sure to take a hard look at the snapped ones. Not sure I'd buy that brand.

[orphancrippler]

Thanks for the info. Do the sway bars on yours make a noticable difference on understeer? I used to own a GTI and as good as the s6 is it is porky and tends to understeerWelcome!

I personally decided to forego the front sway and just do the rear with adjustable endlinks from 034. Also recently added an Alu Kreuz, but the biggest improvement was the rear sway. I believe mine is set on the middle setting right now. Car is much more planted and stable in fast corners.

The reason I did not go for the front as well was because of some people saying it made the front too stiff and tight, but everyone has their own preferences.

Sent from my Galaxy S20 Ultra 5G

[Valpo A7]

I think the 2018 4.0 engines have the upgraded turbo oil screen filter.


Being a 2018, do you have any warranty with the car at the moment? If you do have a warranty then adding a tune will likely flag the car if they find it so powertrain warranty work will get voided.

[Mr.Creasy]

I think the 2018 4.0 engines have the upgraded turbo oil screen filter.


Being a 2018, do you have any warranty with the car at the moment? If you do have a warranty then adding a tune will likely flag the car if they find it so powertrain warranty work will get voided.



Yes I have 7 months remaining on the factory warranty and will likely extend it depending on how long I plan to keep the car. I've heard that JB4's wont be detected if warranty work is done, as long as the piggy back is removed before taking it to the dealer.

Thanks for everyone's feedback!

[Optimus247]

Yes I have 7 months remaining on the factory warranty and will likely extend it depending on how long I plan to keep the car. I've heard that JB4's wont be detected if warranty work is done, as long as the piggy back is removed before taking it to the dealer.

Thanks for everyone's feedback!

Only 7 months ...?? I think you meant a year and 7 months ... 4yr/50 Kmiles is factory ... check your your car's birth Month ...

[Alabama]

I've heard that JB4's wont be detected if warranty work is done, as long as the piggy back is removed before taking it to the dealer.

Maybe true, but read thread "Best piggyback system". A very knowledgeable person John@dynospectrum wrote "There are many ways even I can think of that a piggyback could be detected on this platform, and OEMs have the motivation and means to do so." It's probably very unlikely to develop a warranty issue while using a piggyback, but if a warranty issue arises Audi corporate may still argue the claim if they infer a piggyback has been used.

[jrhgto]

Only 7 months ...?? I think you meant a year and 7 months ... 4yr/50 Kmiles is factory ... check your your car's birth Month ...

Many 2018 models have "in service" dates in 2017.