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C5 RS6 Avant


New member
Hi Guys,
I just pick up a C5 RS6 Avant in Sydney. It's done 112,000k and needs a tidy up. From what I can gather it's the car that stormtroper sold in Perth.
A couple of things you may be able to help with,
First thing is it has KW coil overs and it rides way to hard. Backed off the dampening but it has not helped. Anyone running these? Would I be better off going back to the DRC Shock?
Did oil and filter and noticed the sway bar engine bracket has cracked. New one on the way. Not sure what has caused this.
Also looking for a copy of an owners manual.
Sorry Guys,
I should of introduced myself.
I live in Queanbeyan and work as a Production Manager in Fyshwick. Married with 3 kids, well there all grown up now.
I have been into cars all my life. restored a few GT falcons and was a founding member of the Falcon GT car club of Newcastle. Sold them before the price rise. Just my luck. I have owned and modified a Falcon BA XR6 Turbo over the past 8 years and do as much work on the cars as I can. Its a hobby. we still have the BA as resale is bad. It only has 110k's on it.
My daughter purchased a 2008 A3 Turbo last year and I was very impressed with the build quality and performance. I have always admired the RS6 but could never afford one. The A3 started me searching for something I could afford. Most had 170k's+ on the clock which lead me to the Avant I purchased with 112k's. So far its just been cleaning and maintenance. I just found the KW coil over install manual and will start by checking spring adjustment is within spec.
Hi Greg and welcome. There are a few current and past C5 RS6 owners around who may chime in if they see this. You're local so we might see you at some future coffee morning.
Congrats on the purchase Greg. Sounds like it will be a great project for you and in some ways the older RS models are better than the new ones. :)

As I'm sure you've read the DRCs inevitably leak and I would have thought you could back off the KW damping enough for your liking. Perhaps you need to consider something like Koni FSDs?

You should also get over to RS246.com as there is still quite a bit of activity over there on the C5s and someone will have all the answers for you, if not the search engine.

Look forward to seeing some photos when you get time to put them on.
Hi Greg, That's the problem with KW - they are too hard even on they're softest setting. Unless you track the car KW are not needed. Putting back DRC is not really an option as it will cost you half of the car cost if not more and yes they will fail randomly quickly. Owners in States have used Koni sport shocks with DRC original springs, it's almost direct fit and gives you DRC like ride. Price for Koni is relatively cheap also. I still have DRC and luckily without leaks, but who know how long that lasts. I personally don't see good replacement for DRC and that's really bad.
Hi Guys,
Changed the broken engine bracket today. The problem was the 2 bolts that go into the chassis were stripped. All fixed and back together.
Rest the pre load on the back coil overs to their proper spec. Rear has dropped 20mm. Next I will do the front as the preload is set to high as well. It will need a full wheel alignment after this from what I have read. I have heard that Inline at Queanbeyan are good with doing these types of wheel alignment. Anyone used them?
Front springs reset and wheel alignment done. It rides much better. Also dropped the tyre pressure to 38psi.
Small oil leak from front diff housing. New seal on its way. I think the diff oil is liquid gold. $104 per litre from Audi. At least I know it's the correct oil.
Good work, lucky you can do all of these maintenance things yourself.

Surely Supercheap or somewhere will have the appropriate diff oil on sale for a fraction of the cost.

I don't think there is really anything special about the diffs in the C5.
Second that. I'd check the OS Forums and see what the opinions are. A fully synthetic 75W/ 90 is an appropriate alternative although you won't necessarily find that to be bargain basement priced. There is a Mobil distributor in Fyshwick where you might be able to buy an appropriate oil if there is one in their range that you choose.

(Manual) Gearbox oils are another matter and I would probably choose the factory product for my RS4 despite the various reviews of alternative oils.
BTW is diff and gear oil changed on time and/or mileage and what is it roughly?

These days Audi recommends doing it based on mileage, not time.

Back then though it was probably recommended to do it based on time or mileage, whatever occurred first.
Purchased the diff oil from Audi with the seal. This weekends job.
As for engine oil I have always used Penrite in my cars.
I am running Penrite ENVIRO+ 5-W40 in the RS6. It 502,505 and 505-01 as recommended.
Also replaced the knock sensor connectors as they have gone brittle and fallen apart. Bare pins floating around in the connector mounts on top of the engine. It was more than likely shorting to ground as it flopped around. These are male Bosch 3 pin EV1 connectors. Had to buy them from US EBay.
Hi Guys,
Can someone recommend a VAG Com to buy for the RS6? So much info out there not sure of what to get.
Does any one have a green connector knock sensor and a digital multimeter? The green connectors on mine have fallen to bits. This allows the 3 pins to be plugged in either way. When I got the car these were held in by tape and can go in either way. Inside the connector is a 4.7Mohm resistor. Its on either pins 1-2 or 2-3. Its easily measured. I just need to know when looking at the attached pin numbers what outside pin to centre measure around 4.7Mohm. The other side to centre measures open circuit.
Hi Guys,
Can someone recommend a VAG Com to buy for the RS6? So much info out there not sure of what to get.

It really is up to what your preferences are. I am quite happy to use the HEX-USB+CAN Interface (All VAG, 1995-Current Model Year; Unlimited # of VINs) which is the cable plus laptop arrangement. That has now been discontinued so you might get a great price on one. It will do everything that the later models do except it is not a blue tooth version to use with a mobile or table. So, if you have no hang ups about a piece of cable joining the OBD port to your laptop, it's fine.
Well the seal didn't go to plan. Got down to the last Bolt. The one in the centre of the drive flange. Used a T40 torque bit and the Bolt won't move. Ended up braking the bit of in the Bolt. The bit is hardened. Ended up putting it back together as I can't get the bit out. Working on the ground make access really hard as well. Time to take it to someone that has some knowledge on these. I am not game to start banging and digging an this part that is attached to the front diff.
That's a bit of bad luck. No help here, Auto box C5 is something I have not needed to look at. If it is a quality T40 bit that broke then it sounds like you might need to use a pneumatic rattle gun system. All the torque multipliers and "bigger hammer" options still end up at the T40 interface issue.
Hi Guys,
Does anyone know what this interior colour is called. Cant find much on google. It look white with black lace.

Audi RS6 Codes.jpg
QJ = Silver/Soul.

Seats are a silk nappa in 'Silver' colour, with 'Soul' black piping.

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