Looking to purchase a C7 S6 or A6, daily driven reliability questions

[billbB7]

TL;DR: Looking for inputs on C7 S6 daily driven reliability. S6 vs A6 reliability. Help me avoid an SUV family hauler

I'm currently in the market for a new to me vehicle to replace my B8.5 S4. Up until now I've been firmly in the "save the manuals" camp, but a growing family and need for daily convenience has started to take precedence. I'd like to keep my daily driver somewhat current (read: newer, reliable, somewhat low miles) and not many newish manual transmission sedans interest me at this point. C7's are at the top of my list based on aesthetics alone, both A6 and S6 are feasible options. Most extended family roadtrips are dedicated to my wife's SUV, but having the option of taking my car is a plus if she can drive it when needed.

I'm most interested in dependability and daily driveability with some fun factor (some posts I've seen say the A6 will feel like a slow boat compared to my B8 S4). Any modifications will be minimal for the next few years as getting to/from daycare and work is most important. Plus I still have my B5 to scratch my tinkering itch and row some gears every once in a while. My B8.5 S4 has been bulletproof with the 3.0T and 6MT, but reading about DSG mechatronics failures on that platform have me atleast second guessing the S6 as an option. From research I've done, similar issues exist with C7 S6 DSGs and the A6 ZF8 is likely the more sensible option... but how many more opportunities do I have to buy a relatively new V8 ICE. Hoping to get some feedback to convince me this isn't a big issue, as a low mileage S6 is the limit of what I'm willing to spend.

Joining a couple facebook C7 groups surprised me with the number of posts I'm seeing about people purchasing extended warranties for these cars. I've never even considered a warranty past Audi factory, and typically I buy ~4 model years old at CPO. My main focus is 2017 or 2018, however it seems I'm a little late to CPO possibilities with C7s. Any feedback on peoples experience with extended warranties is appreciated (through Audi or 3rd party).

From what I've researched for S6: turbo oil screen failure (possibly fixed for late model C7s?), PCV, motor mounts, and control arms are common failure points on these cars. Setting my own time aside for maintenance has been a challenge with young kids. In a pinch I don't mind doing my own maintenance, and if anything I've learned more than I thought I would with B5 ownership. From that experience motor mounts and even turbo swaps are within my wrenching ability as long as the turbos don't grenade the entire engine. In general I'm hoping to avoid all of this with a lower mileage car, under 50k miles preferred. Given the high likelihood any potential maintenance for the next few years will need to be done by a shop, my hope is many of these items aren't creeping up until close to 100k miles. Maybe this is optimistic

Any feedback on car seats with the C7 is also appreciated. 2 car seats (one forward facing, one rear facing) in my B8 S4 with my wife in the passenger seat has been doable, but tight. I'm hoping the slightly larger C7 chassis will provide some relief there without completely killing driving dynamics by going to a larger SUV.

[WatchMeSpend]

The A6s have proven to run 11s with a DP setup. Obviously it's going to handle different given it's size. My B5 ate wheel bearings and had horrible brakes and you couldn't put 4 adults in it (broke a spring). My buddy's B7 ate wheel bearings and had terrible brakes. His B9 has terrible brakes, but we will chalk that up to cheap brake parts and we're not sure about the wheel bearings yet. I've had a C6 and have a C7 and haven't had any issues with bearings and so far both the cars have exceeded the B5, B7, and B9 in braking capability. I couldn't even imagine the S6 braking faster but it must be insane.

You cannot compare the quality of an A6 to a S4. I've had access to the B7 while I drove my C6 and there was a noticeable difference. Not plastic rattling or anything, just a feeling of better quality which apparently mirrors the A8. Same as the B9 vs my C7. A friend drives the A4s and I drive the A6s and we are regularly in and driving each others cars.

In regards to the mechatronic, my buddy's went in the B7 and I have managed to dodge the bullet. We dropped in a $500 mechatronic from a scrapper and it took a month for it to adapt. I think you can also either order a rebuild kit or send it away to have it rebuilt or maybe the rebuilder has spares. It was not a DSG and it failed, so now you know that any mechatronic can fail.

The C7 chassis is deceptive. It is smaller than it looks. The C6 was larger. I'm 6'1 235 lbs and I notice the difference. They've gouged out the door panels and B pillar plastic to make ingress and egress easier.

Go see Ignition Tube's YT channel. He switched from an S4 to an S6 and he will point out how the S6 is different. No doubt the A6/S6 is a superior long haul machine. I love back roads and the A6 just gobbles them up. It is a nicer place to be. You have to decide the ratio of comfort to sportiness. Back in the day I ran a solid mounted engine with exhaust that ended under the door. Sporty? Yes. Nice to drive? Not really.

[paul-g]

so keeping in mind a few family things, reliability and let's face it fuel mileage can be a factory with today's prices A6 3.0 is an very solid option. I have a C7.5 2016 A6 S-line, just a simple stage 1 with TCU tune and the car woke right up and you will surprise a lot of cars out there. mine did a 12.17sec 1/4mile pass as it's best which isn't to shabby (tail wind probably lol) the TCU tune is the big helper here stage 2 with single pulley is also a solid option but when you go to dual pulley's you start really having to thing about what your looking for. plenty of guys run it and most will tell you no issue but if you want zero issues and stress on your mind i'd just find a point and just drive it, race car or family car. So room as you already know A6 decently roomy, great trunk love my car (i get bored easily) drive it nice smooth and comfy like it should be, drive it hard handles everything the same way....mixed driving (normal driving that is) 26 for me is very easy, all highway long trip i've seen 33mpg in town beating on it well...ya know 17 or so. to me kind a best of both worlds.

this is just my 2 cents doesn't mean anything to anyone else....would i love an RS or an S of course but i also was driving 30 miles each way to and from work and fuel mileage was part of it for me. also picked mine up use with only 40k on it for $22k hard to argue those number and that was 2/2020 pre covid now used cars are worth a lot more and i also drive 0 to work now a days lol

As a side note there is a guy in town with a newer (newer than mine) S4 and we've went at it a few times and i believe him to be stock and i was letting off (single lane road) when we were racing...

[A665]

Get a C7 A6 with Sport/S-Line suspension and add an ECU and TCU tune. Best of all worlds from a comfort, roominess, speed, ride & handling, fuel economy, reliability and affordability perspective for someone who enjoys spirited driving in a timeless vehicle design.
Yes, I'm biased, but the car runs and looks great, holds all my stuff plus 4 people very comfortably, and crushes 0-60 in under 4.5 seconds when you nail the throttle. Frankly, the only thing I long for that a stock S6 has is the V8 exhaust note. I fully realize you can tune an S6 to levels far exceeding what I can do with my A6, but I'm perfectly happy with my humble Stage 1 power level and I'm content with the quiet factory exhaust on my A6 anyway. Sleeper style. And I don't need to worry about the S6 turbos, oil screens or DSG.

[McNeil]

I’ve had a 2017 C7.5 A6 Competition now for almost 2yrs. I’m coming from a B7 Avant.

I absolutely love this car. Looks great, fast enough after my Stg1 ECU/TCU tune and small upgrades.

It is great for long drives. The ergonomics are perfect for comfortable driving. I’m 6’0 and I can have both elbow resting on door/center rests with hands on the wheel.I have the sport seats so the leg extensions are key.

I also have a infant and a rear facing car seat. My wife is able to comfortably sit in the front without adjusting the seat too much.

I miss the hatch of the Avant but a roof rack and Thule box add some extra storage for family trips.

The car is almost silent on the highway and the interior cabin is also free of creaks and rattles which drove me nuts in my B7 A4.

You’ll enjoy the C7 platform!


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[christianb5s4]

Echoing McNeil. I have a 2016 A6 with APR stage 1 and a melen TCU tune (and some minor OEM+ upgrades), it's been excellent. Far more than quick enough for a daily and gets shockingly good gas mileage (average low-mid 30mpg on longer drives). It is also well built and very solid.

I suggest the C7.5 facelift if you can do it, and find one that has the options you want. My must haves were prestige and driver assist.

[Valpo A7]

The 3.0 coupled with the ZF trans is pretty damned solid.

All depends on how hard you beat on the car as to how long it will last. My 12 seemed to be babied by the first owner and I really didn't beat on it either and its at 219,000 miles now. My only big ticket was timing chains at 204K and I replaced the original motor mounts when I put the engine back in. Previous owner believed the Audi fluid for life and did not change the trans fluid so now I am not going to change it. Still shifts smooth despite the mileage.

I like the 7 over the 6 but its a 4 seater, no middle seat or seat belt in the backseat. Can't speak about rear facing seats but we had a forward facing for my grandson in the back without issues.

[BuickTypeR]

i am selling my a6 c7 3.0t stage 1 tune 034 let me know if you are interested 1 owner 75k miles mint.

[VinnysS4]

I'm at 160k on my c7 s6. Have been stage 3 with RS7 turbos, ds1 and tcu tune for about 20k miles now. In my ownership since 100k I have replaced the turbos, passenger front wheel bearing, and the water pump. All failed before going stage 3. I'm in to the car about 30k with purchase price and all mods. It will do a 3 sec 0 to 60 on street tires and low 11/high 10s in it's current setup. I daily it and never fear of it breaking down (knock on wood) combined mileage is 20 mpg. I can see 25mpg if I put it in efficiency mode on the freeway. Overall the funnest and fastest cat I've owned. I'll pull the engine this summer and do a complete overhaul (I'm ocd on that stuff) but the regular person wouldn't. They have the normal passenger motor mount failure and control arm bushing failures that all Audis have. Nothing new. Brakes are expensive. So are other items, but hey, it's a very expensive car new so I get it.

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[MattyMarkey]

"but how many more opportunities do I have to buy a relatively new V8 ICE"

^ Says it all for me and pretty much why I looked at an S6/7 when my A6 was totaled. Knew going into the purchase regular maintenance was going to be a bit more expensive, but I also do the majority of of it myself. 3.0t with the ZF8 is "muted", is how I would describe it. TCU can help that, but the DSG is a much sportier tranny; shifting and the drivability - take a good test drive! totally different experience and some are not fond of it. I personally love how the dual clutch behaves, but ZF8 wins if you are looking for a mild-mannered luxury sport sedan.

Let's be real... Both are plenty fast for daily driving stock. We all don't "need" over 400hp on these streets, but when it's available, why the heck not?! A6 will be more reliable and cost of ownership will likely be less. 4.0 motor mounts are $1300-1700ish per side (Indy shop). Mechatronic isn't guaranteed to fail, but can get pricey. Oil screen removal is $1500-$2000 (Indy shop). If preventative maintenance and cost of potential repairs is the bigger factor, than you have your answer; A6

[billbB7]

All good responses, thanks everyone. Since it wasn't commented on, I take it an aftermarket warranty isn't a common consideration for people? I'd really only consider this if I purchase an S6. The A6 I have good familiarity with the 3.0T, it's an excellent motor, reliable, and the feedback I'm seeing about the ZF8 doesn't seem to be as problematic.

Agree about the capability and daily drivability of the 3.0T, which is why the C7 A6 is certainly an option. I never tuned my B8 S4, but an ECU/TCU upgrade of the A6 would most likely happen at some point.

[billbB7]

The A6s have proven to run 11s with a DP setup. Obviously it's going to handle different given it's size. My B5 ate wheel bearings and had horrible brakes and you couldn't put 4 adults in it (broke a spring). My buddy's B7 ate wheel bearings and had terrible brakes. His B9 has terrible brakes, but we will chalk that up to cheap brake parts and we're not sure about the wheel bearings yet. I've had a C6 and have a C7 and haven't had any issues with bearings and so far both the cars have exceeded the B5, B7, and B9 in braking capability. I couldn't even imagine the S6 braking faster but it must be insane.

You cannot compare the quality of an A6 to a S4. I've had access to the B7 while I drove my C6 and there was a noticeable difference. Not plastic rattling or anything, just a feeling of better quality which apparently mirrors the A8. Same as the B9 vs my C7. A friend drives the A4s and I drive the A6s and we are regularly in and driving each others cars.

In regards to the mechatronic, my buddy's went in the B7 and I have managed to dodge the bullet. We dropped in a $500 mechatronic from a scrapper and it took a month for it to adapt. I think you can also either order a rebuild kit or send it away to have it rebuilt or maybe the rebuilder has spares. It was not a DSG and it failed, so now you know that any mechatronic can fail.

The C7 chassis is deceptive. It is smaller than it looks. The C6 was larger. I'm 6'1 235 lbs and I notice the difference. They've gouged out the door panels and B pillar plastic to make ingress and egress easier.

Go see Ignition Tube's YT channel. He switched from an S4 to an S6 and he will point out how the S6 is different. No doubt the A6/S6 is a superior long haul machine. I love back roads and the A6 just gobbles them up. It is a nicer place to be. You have to decide the ratio of comfort to sportiness. Back in the day I ran a solid mounted engine with exhaust that ended under the door. Sporty? Yes. Nice to drive? Not really.

Most mechatronic failures I've read about have been from B8/C7 generation forward, but up until now I haven't really considered an automatic. From your comment I guess this can be a common failure point regardless of generation or if it's dual-clutch vs torque converter. Still, a month adaption process seems excessive..

Glad you commented on Ignition Tube's youtube channel, one of his videos was a great overview of options for the C7. That will help for sure during my search.

[VinnysS4]

I dont buy aftermarket warranties because I have my own shop and do my own work. It is usually cheaper for me in the long run. They often dont cover some needed parts. Like on the b6/b7 s4 4.2 most warranties cover the timing chains and not the guides that are the actual known failure parts. In the 50k+ miles I've owned my s6, I've put $1800 in parts into it for failed items. The turbos were the largest cost of that list at 1400. The other 2 items were a wheel bearing and water pump. Neither are uncommon repairs among Audis. The rest of the parts on my car I installed for fun. It is getting some more parts( control arm bushings, motor mount etc) but again, for a 160k mile car, not uncommon for an Audi. Especially one with double the factory power.
If you dont wrench on your car, I'd suggest purchasing an extended warranty for things like the mechatronic unit or injectors(requires an engine pull) and whatever else they may cover. There are a couple good companies that offer real warranties (albeit expensive) The labor cost is crazy at shops that work on these. The turbos and pcv valve have a recall warranty so you should be fine in that department.
On the S6, things like water pumps and other small items have high price tags compared to other models. The water pump in my s6 looks almost identical to the pump in my v6 A4 and it costs 10x more than the A4 pump does. Absolutely nothing special about it either. The brake rotors are stupid expensive. If you get the carbon ceramic option, it gets even more crazy expensive. Windshield replacements need a whole wheel/camera alignment for the Adaptive cruise control and braking guard to work properly afterwards. Audi charges like 300 to 500 for this service. Some windshield shops cannot do the alignment so it's a trip to the dealer. Plus an OEM windshield costs like $1500.
Just things to keep in mind.
These cars are like a high maintenance girlfriend. Keep them happy and they will keep you happy

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[billbB7]

Echoing McNeil. I have a 2016 A6 with APR stage 1 and a melen TCU tune (and some minor OEM+ upgrades), it's been excellent. Far more than quick enough for a daily and gets shockingly good gas mileage (average low-mid 30mpg on longer drives). It is also well built and very solid.

I suggest the C7.5 facelift if you can do it, and find one that has the options you want. My must haves were prestige and driver assist.

Facelift C7.5 and prestige are preferred, or a competition trim if I go with the A6, I know I'm looking for somewhat of a unicorn there though. I had the opportunity of driving my wife's new CX-9 for a while and I ended up liking the creature comforts more than I thought I would... HUD + Apple carplay are a nice touch.

A lot of this may come down to finding a good lower mileage example. The used car market sure is aggressive right now.

[billbB7]

I dont buy aftermarket warranties because I have my own shop and do my own work. It is usually cheaper for me in the long run. They often dont cover some needed parts. Like on the b6/b7 s4 4.2 most warranties cover the timing chains and not the guides that are the actual known failure parts. In the 50k+ miles I've owned my s6, I've put $1800 in parts into it for failed items. The turbos were the largest cost of that list at 1400. The other 2 items were a wheel bearing and water pump. Neither are uncommon repairs among Audis. The rest of the parts on my car I installed for fun. It is getting some more parts( control arm bushings, motor mount etc) but again, for a 160k mile car, not uncommon for an Audi. Especially one with double the factory power.
If you dont wrench on your car, I'd suggest purchasing an extended warranty for things like the mechatronic unit or injectors(requires an engine pull) and whatever else they may cover. There are a couple good companies that offer real warranties (albeit expensive) The labor cost is crazy at shops that work on these. The turbos and pcv valve have a recall warranty so you should be fine in that department.
On the S6, things like water pumps and other small items have high price tags compared to other models. The water pump in my s6 looks almost identical to the pump in my v6 A4 and it costs 10x more than the A4 pump does. Absolutely nothing special about it either. The brake rotors are stupid expensive. If you get the carbon ceramic option, it gets even more crazy expensive. Windshield replacements need a whole wheel/camera alignment for the Adaptive cruise control and braking guard to work properly afterwards. Audi charges like 300 to 500 for this service. Some windshield shops cannot do the alignment so it's a trip to the dealer. Plus an OEM windshield costs like $1500.
Just things to keep in mind.
These cars are like a high maintenance girlfriend. Keep them happy and they will keep you happy

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If this isn't an argument for the S6 being reliable, I don't know what is. Sounds like you found a good one if you've only spent $1800 in parts in 50k miles of ownership! I understand doing most of my own work will help keep costs down substantially, but my hope is a low mileage one wouldn't need much besides oil changes for a couple years. Kicking myself for not acting on a <25k mile 2018 Ibis white one that I saw the other day but now is gone.

Once our youngest gets out of the infant/diaper stage I can see doing most of my own work again.

Agree on wheel bearings, brakes, and control arms as a common theme in most recent generation of Audi sedans. I'd plan for these no matter what I end up with (shop or my own wrenching time), but I couldn't manage an engine out service for my daily at the moment.

[MattyMarkey]

If this isn't an argument for the S6 being reliable, I don't know what is. Sounds like you found a good one if you've only spent $1800 in parts in 50k miles of ownership! I understand doing most of my own work will help keep costs down substantially, but my hope is a low mileage one wouldn't need much besides oil changes for a couple years. Kicking myself for not acting on a <25k mile 2018 Ibis white one that I saw the other day but now is gone.

Once our youngest gets out of the infant/diaper stage I can see doing most of my own work again.

Agree on wheel bearings, brakes, and control arms as a common theme in most recent generation of Audi sedans. I'd plan for these no matter what I end up with (shop or my own wrenching time), but I couldn't manage an engine out service for my daily at the moment.

It’s honestly a gamble with any used 4.0t, newer with low miles or the C7 generation, which is also reflected in the cost of a well-respected VSC company; upwards of $6-7k, depending on year and miles. Also depends how much you drive and how long you will own it too, if it’s worth it.

Have a motor mount failure (very common), control arms (very common) and you’ve already recouped half to 2/3rds the cost. Have a sport diff failure (fairly common) or turbo failure (common), and you’ve saved yourself a boatload of money. All of this mainly if you plan to keep it stock.

If I didn’t buy my car from a dealer in CT, which the state requires used car dealers to give a 90day/3k mile warranty, I would be out over $10k - sport diff replaced and motor mounts. This was on a 2014 S7 with only 11k miles.


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[VinnysS4]

If this isn't an argument for the S6 being reliable, I don't know what is. Sounds like you found a good one if you've only spent $1800 in parts in 50k miles of ownership! I understand doing most of my own work will help keep costs down substantially, but my hope is a low mileage one wouldn't need much besides oil changes for a couple years. Kicking myself for not acting on a <25k mile 2018 Ibis white one that I saw the other day but now is gone.

Once our youngest gets out of the infant/diaper stage I can see doing most of my own work again.

Agree on wheel bearings, brakes, and control arms as a common theme in most recent generation of Audi sedans. I'd plan for these no matter what I end up with (shop or my own wrenching time), but I couldn't manage an engine out service for my daily at the moment.

Ive spent like 6 grand in parts/tunes but only 1800 was in unexpected maintenance cost. The rest was to go stage 3, and I beat on it pretty good from time to time. Otherwise I drive normal. I've seen 2 low mileage example c7 s6 sell for 8grand because they had bad turbos. For less than 15k you could have a 800hp daily. That's if you're into wrenching of course. Otherwise find a low mileage example with a clean pre purchase inspection and you should be good. They all have issues. A6 s6 etc...

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[billbB7]

It’s honestly a gamble with any used 4.0t, newer with low miles or the C7 generation, which is also reflected in the cost of a well-respected VSC company; upwards of $6-7k, depending on year and miles. Also depends how much you drive and how long you will own it too, if it’s worth it.

Have a motor mount failure (very common), control arms (very common) and you’ve already recouped half to 2/3rds the cost. Have a sport diff failure (fairly common) or turbo failure (common), and you’ve saved yourself a boatload of money. All of this mainly if you plan to keep it stock.

If I didn’t buy my car from a dealer in CT, which the state requires used car dealers to give a 90day/3k mile warranty, I would be out over $10k - sport diff replaced and motor mounts. This was on a 2014 S7 with only 11k miles.


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Yikes for the sport diff failure. What was the root cause there? I've heard some issues with this but didn't think it was common. Sports diff in my B8 has been great and it's one of the key specs I'd be looking for in my next car, I like it alot.

I've been meaning to look into motor mount diy's to see how extensive that is. Hopefully just an engine lift with my cherry picker and swap out mounts, although I wouldn't be shocked if there's some electronic adaption needed for that also. Still not what I'd like to plan for near term, but I do have a VCDS cable if that's the case.

One benefit I have is that I'm WFH and don't need to go in to work every day. I need the car to be dependable for kid shuttling more than anything, but that's still only a few days a week and less than 7500 miles/year.

[MattyMarkey]

Yikes for the sport diff failure. What was the root cause there? I've heard some issues with this but didn't think it was common. Sports diff in my B8 has been great and it's one of the key specs I'd be looking for in my next car, I like it alot.

I've been meaning to look into motor mount diy's to see how extensive that is. Hopefully just an engine lift with my cherry picker and swap out mounts, although I wouldn't be shocked if there's some electronic adaption needed for that also. Still not what I'd like to plan for near term, but I do have a VCDS cable if that's the case.

One benefit I have is that I'm WFH and don't need to go in to work every day. I need the car to be dependable for kid shuttling more than anything, but that's still only a few days a week and less than 7500 miles/year.

We weren’t completely sure on RC why it failed, but my guess was because it was driven very infrequently and sat for long periods of time with the original owner. It has happened to a number of people here though. I do believe it’s the exact same sport diff as the B8, and I think it’s failed for quite a few of those also. Seems like something goes wrong with the seals/clutches/pump causing a system fault. They make a rebuild kit for it, which sometimes works (usually only when there’s been a small leak), sometimes it does not. Bring it to the dealer and they will 99.99% of the time tell you to replace the diff itself.

If you have the know-how and resources to DIY the mounts, I think people can replace the passenger side in 3-4hrs - always just a good recommendation to replace both while you’re in there. Slightly Mixed opinions on coding the new mounts… I’ve only been told you need ODIS to code the new mounts, and not able to do so via VCDS. Select people say no coding is needed at all; replace and you’re good.


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[DGr1FF]

Of the issues listed, I haven't seen sport diff failure common. Every thing else agreed. Driveshaft Carrier upgrade is a common, cheap upgrade to protect sport diff. Dollar for dollar the A6 can go very fast for cheaper, but the 4.0T platform is in a league of its own comparatively.