Took my '06 997S for a nice drive today. I'd been driving about 50 miles or so when I started to notice that the car made a "humming" noise when turning left on the freeway. It doesn't happen every turn, but it would do so pretty regularly. Other than the fact that it harmonized nicely with the PSE from time to time (depending on the RPM!), it's got me a bit worried. All my temperatures and pressures were normal and my oil level was fine.

I'm going to take the car to the dealer, but would appreciate any opinions as to what might be causing this noise. Thanks.

 

Seems like a textbook symptom of a bad wheel bearing?

With best regards,
- Alex (07 C2S)

 

09 997.1 TT 63k mi. Have similar noise turning left, lightens up turning right. Noise comes around 40mph then goes away (or less noticeable) after about 60 but back after 75. More pronounced turning left, lightened turning right. But persists even when going straight.

Have replaced right front bearing, didn't fix it. Did right hand shaft too so CV joints are new. Didn't fix it. What else could it be? Drive shaft bearing would make such noise ?

 

My first thought is wheel bearing. I've also heard of tread separation making a similar noise. How are your tires? They can look fine but under the stress of turning the tread can wiggle. If it's not the bearing, swap front tires around and see of the noise moves with it.

 

+1 on wheel bearing. I never had it on the 997 but my Land Rover did the same thing. I thought I had uneven wear on my right front tire but found a scary amount of play in the right front bearing. Your right front bearing will make a noise if turning to the left at highway speed and vice versa. Jack it up and try to wiggle the tire to check for play.

 

You can check this quickly yourself (do both sides). If you're hearing noise when turning left I say check the right side first. The reason I say that is that there's more force on right wheel when you're turning left, and vice versa. Lift tire off ground, place hands at 6 and 12 o'clock and check for looseness. If you feel play it's the wheel bearing. You can also spin the wheel to see if you hear any noise, but with load off the wheel you may not.