I have a 2012 991 C2S Coupe that has started making a very disconcerting noise. When driving, I hear it over my left shoulder and sounds like something banging around in the trunk. Obviously that's not it, but it's the best way to describe it. I suspect that it has something to do with the frame or tire or axle or... It makes the noise when I do something to twist the frame like driving out of my driveway at a sharp angle to avoid scraping the spoiler, or when going over speed bumps or dips in the road. The noise never happens on a smooth road, so I've suspected shocks or the frame. Performance is not affected at all, so I do not think it is an engine issue.

The other day a guy came up to me as I was parking the car and said he's been following me on the road and noticed that something was wrong with my left rear tire. He said it appeared to be wobbling. I feel nothing while driving it though, and adjusting my side mirror to view the tire, I can't see anything wrong while at speed. I don't know if this is related at all.

I'm taking it to the dealer next week to have them check it out, but because the noise is sporadic and unpredictable, I don't want them to tell me, "We drove it and didn't hear anything. Here's the bill." I'd like to take with me a list of items for them to check, but don't know what to ask. Any advice? Thanks!

 

Have someone drive it and follow behind.

 

yeah sounds suspension related..

Read a while back about someones 991 being delivered with the coil spring shipping spacer (not sure what it called, but it was something that is supposed to be removed by the dealer during customer prep). Which caused some weird noises... Since your's is a 2012 and the noise is new that isn't the case..

Got a small rock/pebble stuck in my brake caliper a while back after I was in a chunked up parking lot. That noise was awful but sounds like yours is more subtle.. But that is something I pay attention to now.

Let us know what it turns out to be...

 

If the spotter is accurate, it sounds like a worn wheel bearing which would make different sounds based on the loading of wheel (turning) and speed. Suggest you jack up the wheel and see if you have any play in the wheel. If you are not mechanically inclined then placed your hands on top of the wheel and try to move the wheel toward and away from you. If there is play in wheel, then its likely a worn wheel bearing.

 

Good advice.. But if the rear wheel is wobbling enough for someone to a) notice it and b) notice it was significant enough to point it out to the driver. I would be worried the entire assembly is about to depart from the car...

I've had bad wheel bearings (not on Porsche's) but usually they can be heard load or no load.. And even at that I'm not sure the wheel wobbled..

Sounds like something really bad is going on.. I'd flatbed it and play it safe.. I had a wheel come off a truck one time years ago with a bearing failure and it isn't fun or pretty..

 

Precisely why I recommended pulling the wheel. My thinking is that there might be a severely bent rim to cause the wobble effect. If this is the case, the bearing is likely shot. In my experience a severely worn bearing that is causing a wheel to wobble, will have play in it even in a P-car.

 

FWIW, I jacked up the car and don't feel any play in the wheel at all. I will make sure the service guys check the bearings though. I'll let everyone know what the results are on Wednesday. Thanks for the advice.

 

When you had the wheel off, did you rotate it? Any noise?

 

@991carreradriver Good point on the bent or damaged rim...

But going back to the observer who saw something funny visual.... If he's not seeing any significant wobble with the wheel mounted (and I'm assuming he spun the wheel while jacked up) I still start thinking somethings messed up with the strut/spring/suspension.

Conjecture is more fun that reality, lol but I suppose we will know soon...

 

As you may have surmised... I am not mechanically inclined, but I did jack the car up, put it in Neutral and manually turned the wheel. It does make a noise when moving back and forth which does sound similar to the noise I'm hearing, but I don't know if it's normal to make the noise when doing this. I posted a quick video to Youtube here and moved the camera close so you could hear it. Hope it helps. The wheel doesn't just spin freely, so I'd never be able to tell if there's a visible wobble. If there's another method, please let me know.

 

Well that does not sound like a bearing issue. Manual or PDK? Sounds like is coming from the drive shaft, though I have never heard of problem with the shaft before. When you are in for service, be sure to show them the video. It will help them diagnose the issue. In my PDK, I get that sound when I move the rear wheel in park. I don't think the sound presented in neutral. I will be changing brake fluid this weekend, so when my wheel is off i will check out and see if I can reproduce the sound.

 

It's a PDK.

 

Yeah I agree doesn't sound like bearing.. But to be honest I've never rocked the wheel back and forth like you were doing. Sounded like some play in the trans.. but I'm not sure if that is normal or not.. But I have to admit it sounds a bit obnoxious.

 

It definitely makes that noise when moving the wheel in park. What I will determine is whether or not it makes this noise in neutral, I am pretty sure that it does, but my memory is not what is used to be! Hell, I don't do that bad for 63, ugh!

 

Get thee to a dealeree!