Hello all, newbie here. 
 

I am looking to purchase an A6 Avant C8 (2ltr Diesel). Always liked them but not looking at spending a tonne of money - no more than 25k. So for my budget I’m looking at the C8 with various specs. 
 

My question is, having never owned an Audi, what should I be aware of when looking to purchase. Any common faults etc? 
 

I always try and find forums and do research before I buy and look to share my experiences. 
 

cheers, 

Dean 

West Yorkshire 

I too am a newbie to this forum and would be interested to hear. I’m about to pull the trigger on a 2021 petrol Avant. From what I’ve read so far this model of car can suffer from water ingress in rear pac footwell offside and central locking issues . . . 

Perhaps Dean and Paul it would help to look through the relevent section of the forum for that marque to see what problems owners face, though bear in mind only bad news is written there. We rarely get to hear the good news.

21 hours ago, cliffcoggin said:

Perhaps Dean and Paul it would help to look through the relevent section of the forum for that marque to see what problems owners face, though bear in mind only bad news is written there. We rarely get to hear the good news.

I would have thought this was the correct section, no?

Water ingress is proving an increasing problem. Check the service history of the car you're looking at. It might be due auto gearbox oil service etc. 

Thanks Steve

C8 models 2019 onwards. 2.0TDI engine is robust and will be paired with 7-speed S Tronic gearbox. That needs serviced every 38k miles. V6 variant, then 8-speed TipTronic.

Diesel 2.0 litre will be timing belt, so renew along with auxilliary belts every 60k miles plus water pump, etc.

Personally I’d look for Quattro. That adds a few mpg but it’s surefooted and will help sell thereafter.

Like anything, servicing is key. You want paperwork and lots of it. Avoid long service intervals. These are also sensor heavy, so consider purchasing VCDS as checking and clearing codes is £200 from Audi.

All diesels, then you’re into AdBlue (Euro6), EGR, DPF, etc. Not sure when mild hybrid system started on petrol and diesel, but it’s complex. Search VAG Technic. It might have been an A8 but it caused them grief to fix.

Faults, then rear coil spring seats are known weak point. The alloy corrodes from within the rubber. Rear subframes are just powder coated, so get there with Lanoguard. Front multi link suspension usually good for 100k miles, but will be hydrabushes, etc. On car around 50k miles, then potentially some arms if any knocks. Lemforder or Meyle HD.

Another option is A6 Allroad, that’s air suspension.

Extras worth getting, matrix headlights, auto towbar if you tow, full panoramic. It’s all money, but something to consider.

I have a 50tdi 2018. It is an excellent drive, so good I have kept it since nearly new (ex demo).

Probably the nicest car I have owned in 40 years but also the least reliable by a massive margin but I like it so much I have kept it. Not cheap to repair as the normal garage diagnostics are kept out of half of the modules so main dealer the only option.

On 9/25/2025 at 3:37 PM, Dean_1452 said:

Hello all, newbie here. 
 

I am looking to purchase an A6 Avant C8 (2ltr Diesel). Always liked them but not looking at spending a tonne of money - no more than 25k. So for my budget I’m looking at the C8 with various specs. 
 

My question is, having never owned an Audi, what should I be aware of when looking to purchase. Any common faults etc? 
 

I always try and find forums and do research before I buy and look to share my experiences. 
 

cheers, 

Dean 

West Yorkshire 

Hey Dean. I had a C7 for 4 trouble free years. I bought a 2023 C8 in July and, so far, its been off the road for a month.

My advice is don't buy a C8 onwards. Even the C9's are littered with problems and service garages are full of brand new cars getting software updates. 

I'm stuck with mine unless it develops another fault, then I'll drive it through the dealership window! 50k for a car that's been off the road for a month and Audi washed their hands of their warranty obligations.

On 11/22/2025 at 3:19 PM, Ian123 said:

I have a 50tdi 2018. It is an excellent drive, so good I have kept it since nearly new (ex demo).

Probably the nicest car I have owned in 40 years but also the least reliable by a massive margin but I like it so much I have kept it. Not cheap to repair as the normal garage diagnostics are kept out of half of the modules so main dealer the only option.

Just bought one ....

Tell us a bit about it H.D.

What’s your name by the way - we like to be friendly and address members by their name? 
Regards,

Gareth. 

 

Can see you have returned to the forum H.D, so any updates? 

2020 A6 Avant 50 tdi mhev , had it a week and few things I want garage to check, fan seems to be staying on a few mins after every trip, ZF gearbox hesitant and also feels like it slips in 1st and 2nd although maybe just a comfort thing, reversing camera stopped but is back on, vibrates a bit on full lock pulling away, understand maybe a quattro plus issue..

Expensive car so didnt think id have these issues..

Hayden

56 minutes ago, Ach well said:

Hayden

Thanks Hayden. I have amended your profile accordingly.

Private or dealer sale Hayden?

26 minutes ago, Magnet said:

Private or dealer sale Hayden?

Dealer

Well  surely you are notifying the selling dealer and instructing them to rectify the faults. I would definitely not be investigating the causes of the faults and certainly not trying to rectify them. If you do so, the seller could reasonably counter your claim and conclude that you have aggravated them.

Simply e-mail the selling dealer, outlining the issues and requesting that they advise you how to proceed to get them rectified without any contribution from yourself. 
Please let us know how things proceed, but I would recommend you don’t delay reporting this and getting the issues rectified. 
Regards,

Gareth.

9 hours ago, Magnet said:

Well  surely you are notifying the selling dealer and instructing them to rectify the faults. I would definitely not be investigating the causes of the faults and certainly not trying to rectify them. If you do so, the seller could reasonably counter your claim and conclude that you have aggravated them.

Simply e-mail the selling dealer, outlining the issues and requesting that they advise you how to proceed to get them rectified without any contribution from yourself. 
Please let us know how things proceed, but I would recommend you don’t delay reporting this and getting the issues rectified. 
Regards,

Gareth.

It's already booked in Gareth, was more waiting on comments if anyone else would advise if anything similar as dont know Audi well, used to merc for last good few years.

 

You hopefully just don’t need to concern yourself the ‘has anyone else had the same problem’ Hayden - you have. Best option in my book is to ensure the issues are corrected. 
Please let us know how things progress.

Kind regards,

Gareth.

p.s. If it were mine, I would keep in mind the option of rejecting the vehicle within 30 days if you are not happy with the outcome.