Mysterious disappearing vibrations at 140 km/h - common C6 problem
05-05-2019, 05:45 AM
#1
Mysterious disappearing vibrations at 140 km/h - common C6 problem
Hi C6 users, You are all my last hope 
For over 2 years I'm struggling with mysterious vibrations at high speeds from 130-140 km/h (now noticeable even at lower speeds). Occasional body vibration occurs - I feel it mostly on the seats and whole car body. Occasional means it disappears in a moment to come back in another without any particular reason - driving same speed straight at highway. I have heard already from many users trying to solve the same problem, all types of C6's, all gearboxes and engines versions, quattro and normal versions, standard and pneumatic suspension, face lift and before face lift.
What I have noticed over my "journey" is when car stays on the lift with wheels hanging down for few hours then drive is smooth and perfect, like a new (other users confirmed the same experience). After some kilometers after vibrations starts all over again.
My car is 2,4 Avant Quattro with 182,000 km millage.
So far done:
- new gearbox (manual HGV type, fitted with new bearings by professional company)
- new suspension front (upper swingarms and bottom rubber sleeves exchanged)
- new front end sub-frame bushings (rear side, front looks okay).
- new driveshaft - driveline (SPIDAN new part).
- new internal and externals joints - front (wheel and gearbox side)
- new engine mounts
- new dual mass flywheel and clutch (LUK complete set)
- new rear shock absorbers
- new front wheels bearings
- new gearbox, rear differential and power steering oils
- tires and rims - checked on 3 other sets
- steering joints seems to be okay, checked by few diagnostics stations
- wheel alignment checked and confirmed to be okay
- all 4 tires are the same
- rim hub flatness seems to be okay
- break discs perfectly flat
Did anyone of U experienced the same issue?
Looking forward for any suggestions.
For over 2 years I'm struggling with mysterious vibrations at high speeds from 130-140 km/h (now noticeable even at lower speeds). Occasional body vibration occurs - I feel it mostly on the seats and whole car body. Occasional means it disappears in a moment to come back in another without any particular reason - driving same speed straight at highway. I have heard already from many users trying to solve the same problem, all types of C6's, all gearboxes and engines versions, quattro and normal versions, standard and pneumatic suspension, face lift and before face lift.
What I have noticed over my "journey" is when car stays on the lift with wheels hanging down for few hours then drive is smooth and perfect, like a new (other users confirmed the same experience). After some kilometers after vibrations starts all over again.
My car is 2,4 Avant Quattro with 182,000 km millage.
So far done:
- new gearbox (manual HGV type, fitted with new bearings by professional company)
- new suspension front (upper swingarms and bottom rubber sleeves exchanged)
- new front end sub-frame bushings (rear side, front looks okay).
- new driveshaft - driveline (SPIDAN new part).
- new internal and externals joints - front (wheel and gearbox side)
- new engine mounts
- new dual mass flywheel and clutch (LUK complete set)
- new rear shock absorbers
- new front wheels bearings
- new gearbox, rear differential and power steering oils
- tires and rims - checked on 3 other sets
- steering joints seems to be okay, checked by few diagnostics stations
- wheel alignment checked and confirmed to be okay
- all 4 tires are the same
- rim hub flatness seems to be okay
- break discs perfectly flat
Did anyone of U experienced the same issue?
Looking forward for any suggestions.
Last edited by mat694; 05-07-2019 at 05:57 AM.
05-07-2019, 05:29 AM
#2
AudiWorld Member
Do you have a spare set of tires to swap out? Friend of mine had one of these mistery vibrations and the only thing that would fix it was a different set of wheel and tires (switched to his summers).
05-07-2019, 05:31 AM
#3
I’ve had the same issue on a Fiat Punto. Balanced the wheels twice but still it vibrated. Only swapping to another set of wheels and tyres suddenly fixed it. I guess they were out of balance longitudinally, not laterally.
05-07-2019, 05:32 AM
#4
AudiWorld Member
Ah I misread, see that you did do that. In that case I would guess a worn suspension bushing sowewhere, it wouldn't show up on alignment but can fail to keep up under road conditions.
05-07-2019, 05:47 AM
#5
Thanks for feedback.
As You can see there is no way that tires/rims is a root cause - already 3rd set and no change (including Hunter balancing machines with road test).
I'm tired with blind exchanging everything as I have already replaced parts worth 3k Euro. I know this problem is spreading among all C6's models and after 2 years I'm looking for someone who already experienced same case. At front end I have literally no idea what else to exchange.
As You can see there is no way that tires/rims is a root cause - already 3rd set and no change (including Hunter balancing machines with road test).
I'm tired with blind exchanging everything as I have already replaced parts worth 3k Euro. I know this problem is spreading among all C6's models and after 2 years I'm looking for someone who already experienced same case. At front end I have literally no idea what else to exchange.
05-07-2019, 05:47 AM
#6
Na, he did not change tires if I understand well. He did change wheels but not tires. I had vibrations too at some point and they vanished when I changed all four tires with Yokohama Advan Sport used ones. Handling was perfect with these tires. Not a slightest vibration even at 210km/h (130mph) Only downside is noise. Two of them exploded during a recent trip on a bad road. I replaced them with Michelin used tires and vibrations are back again at high speed. Probably one or more bad tires but I am not ready yet to invest in another set of new tires.
Check this out: https://www.audiworld.com/forums/a6-...thing-2943529/
Check this out: https://www.audiworld.com/forums/a6-...thing-2943529/
Trending Topics
05-07-2019, 06:14 AM
#8
Before disregarding the wheels, make sure you did fit perfect new tires, not just used ones borrowed somewhere else. If you did try this, ignore me.
05-07-2019, 07:34 AM
#9
Sorry mat694, that’s forums for you!
If you feel it’s a problem which affects more cars as they age then maybe think about how the engine changes as it ages (since that’s the major source of vibes in any car). Maybe some kind of shimmy and shake from engine timing losing synchronicity from one side to the other. I don’t know. You said you already changes engine mounts though. Wouldn’t be simple to fix if that was the case though.
If you feel it’s a problem which affects more cars as they age then maybe think about how the engine changes as it ages (since that’s the major source of vibes in any car). Maybe some kind of shimmy and shake from engine timing losing synchronicity from one side to the other. I don’t know. You said you already changes engine mounts though. Wouldn’t be simple to fix if that was the case though.
05-07-2019, 09:29 AM
#10
Sorry mat694, that’s forums for you!
If you feel it’s a problem which affects more cars as they age then maybe think about how the engine changes as it ages (since that’s the major source of vibes in any car). Maybe some kind of shimmy and shake from engine timing losing synchronicity from one side to the other. I don’t know. You said you already changes engine mounts though. Wouldn’t be simple to fix if that was the case though.
If you feel it’s a problem which affects more cars as they age then maybe think about how the engine changes as it ages (since that’s the major source of vibes in any car). Maybe some kind of shimmy and shake from engine timing losing synchronicity from one side to the other. I don’t know. You said you already changes engine mounts though. Wouldn’t be simple to fix if that was the case though.
Any way problem is affecting also one head 4 cylinder engines.
Mysterious
In Poland on another forum we have multiple users experiencing the same problem therefore I believe it touches each C6 finally.