used Audi A6 (C6/4F) - 2004-2011, Complete Buying guide with Common Issues

Buying a used Audi A6 C6 / 4F - produced from 2004 to 2011

How reliable are the engines, how good is this car, what are the common problems, weak points of these cars? What is the price for fixing the various issues? Watch the video and you will get answers to all these questions and more!

What to look for when buying a used Audi A6 C6 advice / guide

used third generation Audi A6

used Audi A6 sedan / saloon
used Audi A6 Avant / estate
used Audi A6 Allroad estate

Audi A6 2.0 TFSI, 2.4 V6, 2.8 FSI, 3.0 TFSI, 3.2 FSI, 4.2 V8, 4.2 FSI,
Audi A6 2.0 TDI, 2.7 TDI, 3.0 TDI

0:00 - Intro + price
1:10 - Interior
3:26 - Body, rust protection
5:23 - Possible issues general
8:51 - Water leaks into the interior
10:18 - Suspension
13:45 - Petrol Engine issues
17:32 - Diesel Engine issues
20:57 - Timing chain/belt
22:06 - Transmissions
24:03 - Ending/Summary
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different car review

[gladius]

Done a lot of work on A6 C6s. Here are some recommendations to minimise issues:
1) Get the facelift version (C6.5) if possible. Many of the earlier faults have been ironed out. Also you get LED lights (although not headlights).
2) Always perform regular oil changes using VW 507 spec. If you do high miles and run extended service intervals then an anti-friction/cleaning additive will help minimise risk of issues (N.B. only do this outside warranty).
3) Use premium fuel and regularly add fuel cleaning additive. Minimises issues with the fuel system such as injector blockages and top-end engine deposits.
4) Never touch a Multitronic CVT car. Best to go for Tiptronic.
5) On a 3.0 TDI, change the crank pulley flywheel. This will often come off at some point as the originals are rubber (not mechanically) bonded to reduce harmonic vibration. When it comes off you will lose cooling, power steering, alternator. So as this failure will disable the vehicle a pro-active replacement will provide peace of mind.
6) Even on the 'sealed for life' Tiptronic auto transmission (which is a great transmission), it is still a good thing to change the transmission oil at intervals if you plan to keep the car for a long time. Only use an approved ZF service partner for this type of work (all of which are listed on the ZF site) as this is a fairly complex procedure and a mistake will cost you dearly. If you service the trans every 50k then there is a good chance that the transmission will outlive the car.
7) Keep a close eye on the rear springs. They often fail at high mileage especially in countries that use road salt in wintry conditions. This is because they rust in a way which allows stresses to build up and they snap.
8) All Audis including C6 have a complex front suspension with multiple control arms to create a 'virtual pivot'. What this means in practice is that there are loads of rubber bushes that will wear out so the handling increasingly deteriorates over time with squeaks and bangs developing in the worst cases. The side nearest the kerb will be the first one to go as that is the one that gets hammered the most due to potholes and other road defects. The upper control arms are the weakest so you need to keep an eye on those for undue play, especially the rear one. Unfortunately rubber bushes will fail even on lower mileage cars because rubber is a component that ages irrespective of use. To avoid that happening consider replacing with polybushes, although they behave differently to standard rubber so this will change the feel of the car quite a bit.
9) Avoid cars with air suspension. Very expensive repairs if you use an Audi dealer. Yes the ride is great when they work but unfortunately with age and mileage then something is likely to eventually fail and the parts cost a lot. If you are unlucky it can be like 'whack a mole' - solve one issue with the air suspension and another is waiting to appear.
10) Get a Quattro. A C6 without having quattro is like having a birthday party without any friends, just not the same.
11) The SE version has a better ride than the S-Line especially on bumpy roads. Yep the S-Line looks better with the big rims and is a bit better at hard cornering but there is a price to pay for that, which is your comfort. If you get the S-Line then rest assured that you will eventually grimace in advance of every bump in the road or swerve to avoid them.
12) If you plan to own this car then you will need some DIY car skills, and so is probably not a car to own if working on a car frightens you. The newest ones are now 10 years old and they are increasingly getting issues. Having these repaired at an Audi dealer or even an Independent specialist is going to be a very quick way to empty your wallet.
13) Never get a C6 TDI equipped with a DPF if all you are going to be doing are local and short journeys. These engines need to be worked hard to get the high temps necessary to remove engine deposits and local journeys mean the deposits build up and the auto-regen may not be able to handle this. This situation could cause emission control failure (limp mode etc) and potentially require expensive ($1500+) repairs.
14) If you are technically minded, invest in VAG-COM/VCDS and a laptop. This way you can run diagnostics scans, getting the same info as Audi and identify impending issues without spending $$$. You can also make adaptations and activate functions which are not otherwise accessible.

[bauuau]

Broóoo. U must love Audi. You have not put this much detail into any other video !

[komentierer]

On Tesla vehicles, inconsistent gaps actually indicate that the car is completely original.

[GarryMcGovern]

I've had my A6 3.0TDi Avant 10 years now (it's an 07 that I bought at 2 years old). In all that time, I've had the heater valve, leaking tailgate pipe and drivers door regulator issues - but my car has now over 205k miles: or approx 330, 000 km's. Only issue with the engine had been a faulty air flow meter: approx €145 delivered from Germany and fitted by myself in less than 10 minutes. I had the ECU remapped the day after I bought it, and though I can't vouch for the exact BHP figure, I have had it up to a GPS recorded 154mph (just over 160mph on the clock), with a tiny bit more to go (so nearly 250kph real speed), and I am more than happy with that for a big diesel dog carrier!! Still looks and drives perfect (touch wood!), and have absolutely zero plans on changing it any time soon: it's fast, comfortable, has a massive load space, Quattro for the awful weather and on super-long motorway journeys, I can easily get 1000km's to a tank of fuel - the perfect all round car really!

[aguafria]

People from outside Europe won't understand why you focus so much on body panel gaps and hidden accident damage. 😂 Must be nice to live in a country that has trustworthy people

[billturner]

lots of information in this video it's the best one I have seen,
I have a 2005 Avant sline 2.0 tdi with 227.000 miles on it
I have replaced 1 turbo 1 rear spring 2 rear brake caliper the same side both times
Oil pump failed but I pulled over instantly so no other damage
The heater blows full hot on the driver side every now and then I cleaned the valve once already must do it again
The inside flooded through the fire wall I got a stick and knocked that fancy drain valve out now there is a 1/2 in whole no more problems
I had to pull up the carpet to get the water out of the inside about 20 liters can live unseen under there be warned,
It ran rough for a year during that time I changed all the sensors and MAF EGR and a few vacuum lines each time it got better
Now it runs like new again
The rear window regulator is broken right now and the driver door lock won't work with the centeral locking so I use the key.
I love the car still after 8 years and it's unbelievably economical I get 47 mpg over all and 60 on a gentle motorway
Run
It's towed my 1700kg caravan and family all over Switzerland this summer.
It's a good car but luckily I have a very good and trusted garage to do all the work also another car to drive while it's in bits.
Audi I think made an unbelievably high quality car for the money
Lots have gone wrong on mine but nothing was highly expensive as I always fit remanufactured parts and honestly do you expect no problems on a 160.000 mile 7 year old car you bought 8 years ago that's now got 227.000 miles ??
Again I love this video

[Glandorf]

I bought my A6 in November 2018 with just under 200k on the clock, it's 2009 year of production, facelift model with 2.7 engine and 190 hp. To this date I had no problem whatsoever, just regular maintenance. Currently it has 250k, inside almost like new, everything is solid, spacious, comfortable, made for cruising through multiple countries. It's the car I always wanted but wasn't able to buy one, now from my experience I can say that the car is really really great and I haven't regret one bit buying it 👍👌

[maksyi]

I own a6 2005 limousine and i can tell i had exact same problems . Nice quality video.

[RomanTrollanski]

Thanks dude! I am a 2007 Audi A6 C6 4F, Avant, Quattro S Line, 3.2L, owner here. None of the mentioned problems yet, I am at 200k only.
Definitely the drain holes needs to be cleaned!

[daboogie]

I have 2005 2.0TDi A6 BLB engine, with PD injectors and hex shaft driven oil pump, on engine replaced twice egr valve,
Engine mount was changed electric one, just because fault in vcds.
throttle body was working but making tick sound at engine shutdown, got good deal on new, so changed.
1rocket broke, left valve open, didn't notice until was changing glow plugs, car was driving fine.
Injectors was checked during rocket change, was ok.

Milage 350k km, oil change 10k km 5w30
Change fuel filter every 2nd oil change.
Own car since 2008.

[Vikturus]

I regret selling mine. I had a 2008 with the 3.2fsi v6 and I swear to this day NOTHING HAS COME CLOSE TO HOW AMAZING THIS CAR TRULY IS! this is the ultimate daily car, I put nearly 140000km on mine and It was the most comfortable car and Decent HP for a daily. I had the Sline NON air suspension with AWD and it was a great car. When I get the chance I will be purchasing another one

[Vikturus]

I had the 3.2v6 of the c6 from 2008. I bought it with 38000km on it and it was reliable Mine had been sitting forawhile so some electrics were funny. After the dealership fixed them it was perfectly reliable. I had it serviced every 10000km and serviced the gearbox at 70000km and it was perfect. Never missed a beat and would highly recommend this model with the 3.2

[bemused]

Awesome video. This is the very first time i have ever been told to keep X amount of money aside for specific repairs to a car. This sort of buying advice should be standard practice by now.

[shumushrif]

I've got a 2008 3.2 a6, this was the most thorough video I've ever seen! My car is leaking oil has timing chain noises the cabin smells like gas when it runs and it vibrates. It's at 240, 000. After seeing this I realize I need to do over 5k of work on it 😂 it's not worth buying a used Audi. I've had mine since it was at 160, 000 4 years ago

[ivangadzhanov]

I was wondering between this car and an a4 b7 1.9tdi, and eventually opted for the 1.9, much simpler, much easier to work on, got polybushes, quatrro converted it and got a "hard" flywheel when my DMF went out, mine is remapped to 150hp and 400nm absolutely no problems, runs like a dream :)

[karlgfy]

Spot on review, I had a 2008 2.7 V6 A6 allroad, suspension air strut failed at 100k miles, £1800 to fix, blue smoke at idle and black clouds at full acceleration, rear window wiper motor failed and leaked rusting the boot and passenger door actuator failed too.

[sodainc]

I love your videos. You have improved sooo much over the years. Keep up the good work!

[billturner]

i have a 2005 avant 2.0tdi its the first of the PD engines i got it in 2012 with 160.000 mils and it now has 235.000 mils in that time fitted a new turbo 400£ new oil pump remanufactured from Poland about 1000£ with all the labor
new MAF 120£ 1 front wheel bearing 2 parking brake calipers same side as i didnt get audi original part i cleaned the heater valve its been ok since new AC compressor 500£ it ran really rough for a year during that time i replaced all the air sensors and in the end i changed the EGR 120£ and that cured it anti shudder valve changed and the altinator clutch changed and the fan tensioner all new brakes and discs thats about it
it drives wonderfully and is incredibly economical a wonderful car your video is good but with some mechanical sympathy i think the 2.0 tdi of any vintage is a good buy.
i had a ford Mondeo for 5 years and it had the same problems come up every month my audi has had issues but once repairs are carried out they dont come back
i plan on keeping it for another 200.000mils
but am interested in getting an audi q7 as the family is expanding
thanks for the videos
keep it up 💪

[badeshka]

Awesome video! I already drive an a6 4f. I watched your videos before I bought my A6 but still love to watch your videos👍🏼👍🏼😃

[strxwberry]

It's amazing this guy is spot on.
I have the seat belt warning sound BRIGHTENen UP MY DAY every time I use it. Especially whilst excelarting hard.