2018 Audi A6 3.0T - Highway speed vibration

[Audi_STL]

I have been battling a vibration problem with my 2018 A6 3.0T that I bought new in January 2019. The car has a vibration that gets progressively stronger above 50mph+. At normal highway speeds, the vibration is very annoying. The car is not enjoyable to drive on the highway.

The dealer has replaced the tires and road-force balanced the new tires. Also, the vibration frequency does not change based upon speed or RPM, it just becomes stronger. This makes me believe the source of the vibration is in the engine or transmission.

The vibration intensity does vary based upon the load on the engine. For example, when I crest a hill and take my foot off the gas, the vibration becomes stronger.
Has anyone experienced a similar issue and been able to resolve it? The dealer has been no help and I don’t know how else to resolve the issue.

[Speedooooo]

Sounds like a bad engine or transmission mount. Did they check those?

[ItsLarryG]

Have they rebalanced the tires? Maybe just a bad job from the factory?

[got_boost]

This is confusing but maybe easy? What I would do to verify what is or is not the problem, I'd get on the highway and do the 50+ where the vibration is. If it's an auto,put it in manual mode and drop a gear so the eng and trans change rpms instantly. Does the vibration change when this happens or stay the same? If it stays the same, I'd say eng/trans is not the cause. The things that stay in the mix are the wheels,since the tires are new they are ruled out,maybe an axle,a wheel bearing?

You could rule wheels out if you put the spare tire on,if you don't have a winter/summer set, 1 corner at a time and drive it to speed each time to verify the vibration is there or not.
Or maybe have a friend follow you in another vehicle and drive on the driver/pass side to see if they can see 1 wheel bouncing as you drive?

A little late but is this vibration felt in the seat/floor or in the steering wheel?

[haroulli]

Did they replace all 4 tires and they are all the same brand? I had that issue with my old B6.

[GuiltyBystander]

I have the same model car bought at the same time, and if that happened to me, I would bring it to another dealership.

[ItsLarryG]

I have the same model car bought at the same time, and if that happened to me, I would bring it to another dealership.

I have two dealers in the area and one is definitely more customer friendly. I agree with this recommendation.

[Audi_STL]

Wow. Thanks for all the quick feedback and ideas. Let me try to add a bit more context…

When we test drove the car before buying it, we told the salesman that the car ran rough and had the vibration. We asked him to have the car repaired before we picked it up. When we picked the car up, the salesman relayed a message from the service department saying that many of the 2018 A6s had similar problems because the cars sat so long due to a recall and that the tires “flat-spotted”. They told us to drive the car for several hundred miles and it should go away. This sounded reasonable so we did as they suggested. Unfortunately, the vibration never went away.

1. Tires: The original tires were rebalanced and ultimately replaced with the same Pirelli Cintrato P7 tires. The new tires were rebalanced once with another machine and then separately road-forced balanced. This did not correct the problem. In my mind, this ruled out the tires. However, I like the idea of using the spare to eliminate any remaining problem with the new tires. BTW, I asked the dealer to swap wheels/tires with another A6 but they wouldn’t do i. I may ask them again.
2. RPMs: I have changed engine RPMs by downshifting while maintaining the same speed. However, there is no impact on the vibration frequency or intensity.
3. Engine/Transmission mount: I agree with this theory. When the engine load changes at highway speed, the intensity of the vibration changes. Maybe the engine torque increases or decreases the pressure on the mounts. When the engine is “braking” the car, the vibration is at its worst.
4. Other possibilities: My other theory is an unbalanced drive shaft to the front. My assumption is that the AWD system runs at a rear bias when accelerating. I also assume that when I unload the engine at cruise speed, it shifts to a front bias. This is when the vibration the most intense.

The dealer and Audi have been horrible to deal with. This is my first Audi and I cannot believe how much contempt they have for the customer. They seem to have no interest in helping resolve the problem.

[got_boost]

Now that I think about it, I'm having a kind of similar issue. It's not every day,maybe once a month or every other, I get a nasty vibration starting at 60-65 and def gets bad around 80+ and absolutely rediculous when I let off the throttle. It lasts for about 2-3? days of driving and then randomly goes away.
After a bit of research I thought it was the drive shaft center bearing. I pulled the heat shield to inspect and the rubber around the bearing was not worn and sagging so I almost want to eliminate that. If I could find a bearing I'd just replace it for peace of mind but I can't find a replacement for the C7 and a new shaft is $1500 so I'll let this this blow apart and show me what's wrong before I spend that much on a guess. I see there is a backyard style band aid to possibly make that bearing last longer,using window weld and smearing it around the rubber of the bearing, and letting it cure for a day. I have everything to do it just haven't had time to do it yet.

[Vinng86]

My assumption is that the AWD system runs at a rear bias when accelerating. I also assume that when I unload the engine at cruise speed, it shifts to a front bias. This is when the vibration the most intense.

Your first assumption is correct. Our Quattro (w/ Torsen differential) cars are heavily rear-biased 20:80 during acceleration but at cruising speed it's 40:60. Still rear-biased but much less so.

[MVR 155]

If the dealership has acknowledged the issue/vibration and taken these actions thus far, it's on them to continue working through the process/issue until it's remedied. It would be a totally different story if you brought the car in with an intermittent/phantom issue they could not replicate and they sent you on your way. The fact that they have replaced parts and performed labor indicates they have verified an issue. You need to stay on them and escalate the issue as necessary through the dealer. If the dealer begins to brush you off or neglects further interest in addressing your problem, contact Audi of America and start a claim through them. Make sure to let your dealer know (if they decide to brush you aside) that you will be contacting AofA. Hopefully you get to the bottom of this as I'm sure it's becoming a really annoying issue.

[Audi_STL]

The lead mechanic at my dealer confirmed the problem both times I rode with him. They had the car for four days on my last visit and magically found a TSB about road-force balancing the tires. I think this was just their way of getting the car out of the shop.

AoA is involved as well but is less helpful than the dealer and is, quite frankly, one of the worst customer service organizations I have ever dealt with. They had their rep drive my car but would not let me drive with them. Not surprisingly, they said they could not replicate the problem. That is impossible if they drove the car under the conditions I described.

I love this car but cannot drive it on the highway without getting frustrated. I adjusted my morning commute to take back roads that keep me under 60mph. It takes me longer but is more serene.

Thanks for everyone's input.

[rexus300]

Even if they are road force balance, they still need to get the assembly below 10 lbs of road force or the the Audi will have vibration on the highway in my experience. Most techs are not good with hunter machines and settle with 15lbs or so of road force or dont even calibrate those machines and still will result in vibration. What tires do you have? Avoid Pirellis for sure they have nasty vibration on highways and are hard to road force balance.

We had a driveshaft replaced on our 2012 Audi A8L with a high frequency drone/vibration that was felt in the seat at above 70 mph but didnt get worse with speed and we had perfect road force balance tires/wheels with Michelins. You need to request a regional factory representative to come to dealership and drive your car and see whats going on they are smarter and give the dealerships some insights. I requested that and the guy found the resonance to be from an unbalanced driveshaft with the A8 having 40k miles on it 5 years ago. Now its at 180k miles with the replaced driveshaft and no vibration. The driveshaft was shipped from germany within the week and replaced under warranty. I had to go back to dealer 3-4x before I spoke to manager to get the regional rep out. My dealer is fantastic.

[Audi_STL]

How did they diagnose the drive shaft?

[rexus300]

If I recall, the regional representative is very atuned to the car and the frequency of vibration and the driveshaft vibration is a high frequncy buzzing vibration that you feel in the seats, arm rest, steering wheel that doesnt change with the road force or the speed of tire but instead comes on at high speed like around 70 mph and stays constant but can get worse with speed if its badly out of balance. They use a vibration sensors placed in the car to detect this frequency band to help isolate it from the tire/wheel vibration frequency.

[MVR 155]

Another suggestion would be to visit an independent tire shop in your area. Make sure to select a shop that works on high end/performance cars with a solid reputation. Have them balance your tires/wheels along with inspect for any bends/defects in the wheels themselves. If they find the issue, have them fully document it and take it back to Audi.

[rexus300]

Another suggestion would be to visit an independent tire shop in your area. Make sure to select a shop that works on high end/performance cars with a solid reputation. Have them balance your tires/wheels along with inspect for any bends/defects in the wheels themselves. If they find the issue, have them fully document it and take it back to Audi.

I second that! There are 2 independent dealers in my area that have a much newer and better version of the Road Force machine called the Hunter Elite or Touch with is 8 years older than the hunter machine at my Audi dealer and they always road forced my tires/wheels perfectly compared to my dealer which cannot even do a simple balance on the hunter machine. Hence the Audi dealer sucks. I would get that done at a good place and get a print out to make sure all assemblies are below 10lbs.

https://www.hunter.com/gsp9700

Go to link and select road force touch and elite and locate one in your area.

[Audi_STL]

Thanks again for all the feedback and ideas. I don't believe the vibration is caused from the tires due to the nature of the symptons. Personally, the drive shard seems the most logical.

However, my diagnostic efforts are on hold as Audi of America has agreed to repurchase the vehicle. If it goes through, I will buy a new A6 and put this ordeal behind me. Still working through the details of the repurchase but hope it gets resolved quickly and amicably.

[DocTJ]

Thanks again for all the feedback and ideas. I don't believe the vibration is caused from the tires due to the nature of the symptons. Personally, the drive shard seems the most logical.

However, my diagnostic efforts are on hold as Audi of America has agreed to repurchase the vehicle. If it goes through, I will buy a new A6 and put this ordeal behind me. Still working through the details of the repurchase but hope it gets resolved quickly and amicably.

which dealer have you been dealing with ? (PM me if youd like )

[rexus300]

Hey I am glad that this is happening as it will give you a great peace of mind. I dealt with horror with my 2011 BMW 535i (F10) model that had a vibration in the chassis between 70-75 mph only that would rock the headrest back and fort a bit that drove me nuts after doing countless road force and replacing the 4 rims. It was a really bad driveshaft or something but BMW was a callosal ass and woudnt listen or buy back car so I sold it within 1 year of buying it . IT can happen with anyone but at least Audi is willing to step up. Audi was very courteous with getitng me a new driveshaft on our 2012 A8, dont ask me how its possible 1 person can get 2 german cars with bad driveshaft... Audi wins here and BMW loses. Audi also allowed new mechantronic and trans on my 2016 A7. Both the A7 and A8 are runing smoothly now. Keep me posted on how it ends up and what new A6 you get.

[daytona rs7]

i had a vibration, only felt at certain speeds (70-75mph).

ended up being a (minor) bent rim.
in my case i knew what it was as i hit the pothole within the first hour of a 7hr road trip. had the pleasure of feeling a vibration at highway speeds all the way to and from my destination.

[krwalkman]

i had a vibration, only felt at certain speeds (70-75mph).

ended up being a (minor) bent rim.
in my case i knew what it was as i hit the pothole within the first hour of a 7hr road trip. had the pleasure of feeling a vibration at highway speeds all the way to and from my destination.

This is an old bump, my apologies. But I currently am having a vibration issue at most speeds that I only really feel in the steering wheel. I hit a massive pothole and I'm fairly certain it started then, but I wasn't commuting due to COVID and didn't really notice it. Now I constantly feel it and hate it.

How did you determine it was a bent rim?

I took mine to dealership and they balanced my wheels, told me one was way out of balance and added weights accordingly. It lessened the vibration certainly but it is still there. I have put a level up against the face of the wheels and found nothing. I need to take them off and check the rear of the wheels too I suppose.

My thoughts for all possibilities are Bent Wheel, Wheel Bearings, or alignment issues.

If it helps, I have the newer RS5 wheels which are forged and I assume are pretty strong.

[Vinng86]

This is an old bump, my apologies. But I currently am having a vibration issue at most speeds that I only really feel in the steering wheel. I hit a massive pothole and I'm fairly certain it started then, but I wasn't commuting due to COVID and didn't really notice it. Now I constantly feel it and hate it.

How did you determine it was a bent rim?

I took mine to dealership and they balanced my wheels, told me one was way out of balance and added weights accordingly. It lessened the vibration certainly but it is still there. I have put a level up against the face of the wheels and found nothing. I need to take them off and check the rear of the wheels too I suppose.

My thoughts for all possibilities are Bent Wheel, Wheel Bearings, or alignment issues.

If it helps, I have the newer RS5 wheels which are forged and I assume are pretty strong.

For me, when I suspected I had a bent rim I went to a tire shop and they just put the rim on the balancing machine and ran the motor a bit to rotate the wheel.

If it's a bent wheel, it's fairly clear as the "height" of the tire will fluctuate if the rim isn't round.

[Valpo A7]

If you hit a substantial pothole then chances are that its bent. Probably front left or front right. A tire shop will be able to inspect and determine how bad its bent as Vinng mentioned. The more I read about dealings with Audi dealers that I am convinced that most Audi dealerships are only good at selling the car. Most seem to suck at fixing anything beyond just replacing parts.

[Alabama]

The more I read about dealings with Audi dealers that I am convinced that most Audi dealerships are only good at selling the car. Most seem to suck at fixing anything beyond just replacing parts.

Probably true of many luxury car dealers. Less interest by consumers in buying and maintaining a car for at least 10 years, even among AZ members. If I own the dealership and most of my customers only want to lease a car for three years and then turn it over, I'll have my service department focus on routine maintenance. And if I do that, I'll have trouble retaining the most talented mechanics. Regardless, I'm sure Choy188 would recommend that krwalkman go to an independent tire shop first to check the wheel.

[WatchMeSpend]

At one of my local Audi dealerships I know that the clientele are leasing. They drive the car in when the check engine light comes on and pick it up when it is done.

I walked in an asked the parts guy for a new battery and that confused him so he got a mechanic who looked as confused and then claimed they needed to see the car to make sure it was the same battery.

Surprised looks all around when I placed it on the counter.

Next time I asked for brake fluid. The parts guy was gone for ten minutes and then returned with a bottle and pointed at the label and said “Those are the words you said to me, right?”

In contrast my buddy used to be the parts guy at the local Ford dealership. If I asked him in the middle of the parking lot for the windshield wiper for a Ford Taurus, not only did he know the part number, he could walk right to it in the stockroom and hand it to you.

However some of the mechanics seemed to be limited in their knowledge of cars. I guess because one minute you are working on a mustang and the next an escort.

An Indy specializes in certain cars usually and can troubleshoot way faster and most of them care, unlike the dealership who just wants warranty work.

[krwalkman]

Lol I certainly feel all of what you are saying. I tend to do most of my own work but I ceratinly cannot fix a wheel. I usually go to my local indy shop for stuff I cannot tackle on my own but they don't do anything with tires or alignments so I resort to the dealer for that work. Besides, I like the weights they use on the tires, this sounds stupid, but they look nicer as a strip of something then cut and stick on rather than the typical fractional ounce weights.

Anyways, I'll get my tires off tonight and see if I can notice anything. I took an exit loop ramp yesterday going pretty fast turning to the right and the vibration all but went away, leads me to believe passenger side, which is the side I hit the pothole with.

I hope they can repair the wheel if it is indeed bent. I definitely have not seen a crack and have been under my car plenty this year. I'm sad because I have maybe 1000 miles on these wheels. GRR.

[krwalkman]

just a quick update here that I forgot to post. The vibration ended up being a very slight bubble on the inside of my drivers front tire. Likely from the pothole from hell.

Tires happened to be pretty new so I was able to replace just one. That's my first ever bubble in a tire on my Nitto NT555s. I wonder if the sidewalls are weak or if it would have happened to any tire with that situation. It also took a small chip from my wheel :(