S6 Downpipe Flex Blowing

A6 All/ S6 All
#1

So, i’ve had my S6 for just over 3 months now and the flex joint have started to go - can only auume this is due to my heavy right foot and age of the pipework.

Anyway, went to see a local exhaust/fabrication specialist today I got told horror stories of work they’d done on other large engine’d VAG cars. The long and the short of it is…£1200!

Has anyone had theirs replaced before? Did it go smoothly or did it end up with a subframe drop etc?

I’ve seen ads for cars that have had them done so it must be a fairly common issue as they get older.

Pics attached to give you a better idea of what i’m on about.

#2

Pics not working so i’ve put them in an album on google:

https://photos.app.goo.gl/evE6kUv0CoqpIaQK2

#3

Welcome to the forum. This would be the forum to be on for help.

I clicked on your link and it just went to an empty page

You can load photos here by clicking this link
http://audirevolution.net/upload-media

It gives you a folder and that will house all of your pictures. you can then link them to the fourm as you wish.

#4

As for the flext pipe.

that is a tough one. It would and can be very expensive as you cant easily get to any of the bolts and even if you could they tend to strip.

So there is a good chance that they would have to drop the sub frame. It can be done without dropping the sub frame all the way but depending on the shop and there abilities you might want them to do what they deem best.

Overall If you don’t hear an exhaust leak I would wait as long as possible as it is a possible expensive fix. If you have pictures of your flex section and its condition post that this way we can tell you if its just the outter mesh or something more serious

#5

Well, found a local Audi specialist that’s done that kind of work before and they only want about half the original quote which seems a bit more reasonable to me. I know it’s a fair bit of work but unless that exhaust shop was charging dealer labour rates, their estimate was excessive.

#6

Yes good. That labor rate was a rip off. Let us know how it goes. If you can get before and after pics that would be IMHO in your best interests.

#7

I’m late to the game here on this, but I had leaking flex pipes on my S6 this time last year. I took the same route as you and had an independent shop do the work. All in, I think it was around 1200 USD for the 4 flex pipes to be cut out and re-welded. I had them address the rest of the hardware on the exhaust system while it was being done which brought it up closer to 1600 USD. I live in the rust belt of the US so it was only a matter of time before something else gave out and cause the exhaust system to get ripped off.

Major props to them for being able to get at the 4 bolts essentially right off the manifolds (2 on each side). Given the condition that they were in and how recessed they are… I’m honestly surprised they were able to pull it off AND install brand new studs.

I went to German Auto Specialists in Plymouth Meeting, PA in case anyone in the future finds this and is in the area.

#8

So in the end, only took my local specialist 6hrs and ended up costing almost a third of the original quote from the exhaust specialist.

From the cats-back, i’m on a stainless Miltek so it was just my front two flexis that got replaced. He was, thankfully, able to undo all the nuts and lambdas with no real issues. He did have to drop the subframe slightly for better access. Due to corrosion, a lot of the cat studs got replaced and I had him replace all the steel nuts with brass k-nuts.

For anyone in the East Midlands of the UK, I can highly recommend Arthur of S-Line Automotive in Loughborough.

#9

Oh and while he was there, I got him to check the steering rack bolts. None were loose but he did have to torque them up a bit.

#10

Its great to hear this worked out. Those nuts and bolts are so hard to see let alone get to. After the replacement I don’t think you will have to do that again anytime soon.

#11

Last year i change both of them, they get cracked, oem. And before couple weeks when mechanic drop engine i saw on picture that one have crack and leak. But on havy ride my exhaust getting stretch for about 1.5cm, so probably geting crack because that is weakest point and especial if going on automatic car wash with under washing

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#12

That’s good news = 1/3rd the price is a major win!

BTW - do you know if he was able to get to all 4 O2s on each side with just dropping the subframe a little? Asking because I’m pretty sure I have a lazy O2 sensor (Bank 2, sensor 2 - for cylinders 4 and 5) and this is the first I’m hearing this being done without the engine being removed. If there is some crazy trick he used that would be worth gold to the S6 community!

#13

Please tell me more about this. Is this a known issue? Can it be addressed w/ engine/trans in place?

#14

Mine had the same issue after a bunch of pothole hits resulted in them loosening over time I guess. JimmyBones tightened them the first time, then I had loctite added a few months later after one of the bolts loosened again. knock on wood

#15

I did ask about that and he could get 3 out of 4 - i.e. all but the ones closest to the front of the engine. However, the other issue is the wiring connectors…if you look at my pics in the previous link, you’ll see the cables run up over the gearbox and I don’t think they can be accessed without dropping the engine, at least for the furthest forward 2 on each side. That being said, I suppose there’s the posibility to cut/solder in-situ.

#16

Since I got it, my car has felt rather nervous at high speed and on more uneaven road surfaces - straying close to the white line on country roads would pull you into it etc. I’ve seen a few reports about loose racks on both the S6 and RS4 however, pretty sure they were all american cars - so maybe a LHD rack issue? I figured while he was there, I’d see if it was the cause of my issue also. None of mine were loose but he did nip them up a bit just to be safe.

#17

Thanks for the intel. That was going to be my next question… how the hell did the guy reach the connectors mounted to the side of the transmission?!

Ah well, looks like I’ll just live with it for now and then drop the engine once I get a garage with more room and preferably a lift.