Rear road noise louder with speed? Not tires!
 

Ever since I bought my 2003 Boxster Tip base with 78k miles this past March I've noticed a noise very similar to tire road noise and will get louder with speed. I know it's not tire noise because I just replaced all 4 tires and still the same noise. It seems to be coming from the rear passenger side but it's hard to pin point. The car drives and shifts fine. Any idea? :confused:

could be a wheel bearing

Thanks! Could it also be something within the differential?

Wheel bearing, pinion bearing, or CV joint most likely. Get her up on a lift and start poking around.

I had a similar issue last year on a 2002S w less than 50K mi. It was the rt rear wheel bearing. I figured if one was going bad the others would too
Replaced all 4. Very quiet now.

Thanks guys and exactly how does a bad wheel bearing sounds like?

If the noise is increasing when turning it is most likely a wheel bearing that is damaged. This is the easiest way to diagnose it. Just do some long sweeping turns that puts some load on each bearing and listen. If one bearing is gone there is no reason to replace all of them as long as they are silent.

My 03 S was making similar noises which turned out to be a wheel bearing and bad CV joints. Jones Autowerks in San Antonio, TX did the repair. For about $970 I got two new complete axle assembly's and two new wheel bearings. Car is quiet now.

In my experience, failing wheel bearings sound exactly like tire noise. It also took a tire change for it dawn on me the bearings were shot.

Thanks! What's the typical parts & labor cost to replace 1 wheel bearing at an indy?

The part is pretty cheap; $50-$100. They'll pobably get you for about four hours labor though, so you're probably in the $500 range.

Or you can do it all at once and not have to worry about it for another 100,000 miles: two new rear wheel bearings, new pinion gear, new CV joints/boots + indy labor = $2,200.

Wow wow wow!!! Something I see here a lot is a bit of a rush to the most expensive and "worst case scenario" fixes!

I had a similar problem after a service and it was some sound deadening that hadn't been replaced properly after the work. These clips can slip off in time and all it needs is a tidy up and recoup everything behind your seats & in rear trunk back down....

I'm not saying it is that but its cheap so try it first!

I'll just let the mechanic troubleshoot where the noise is coming from then I'll see if it makes sense. Will update once I get a chance to bring her to the shop. Thanks guys! :cheers:

I'd say its replies with sound advice on these cars and the parts that wear causing such a noise that will be a better clue to their origin , than tales of shoddy workmanship .....

However , I too look at everything when chasing down noises as , as i am at the moment .
Wd40 and blu-tak are my best friends :D


PS : What about just fitting an eBay cat-back muffler system :D

So I brought the car to 2 different shops and one thinks it's some bearing in the differential and the other thinks it's the rear passenger wheel bearing. I'm thinking it's the rear passenger wheel bearing because when I sweep the car left and right I only hear the noise when I sweep to the left and the noise disappear when to the right.

Is it possible that in this case some bearing in the differential is bad as well?

As far as I know, those symptoms could be caused by either problem. I would think the differential repair would be in the $2-3000 range so to me it only makes sense to do the wheel bearing and hope for the best. A rear bearing at Suncoast or Sunset Porsche costs $60-65 and but it'll be far less in an industrial supply house which you could do if you're doing the job yourself; If so, it would be a good time to do the rear brakes, if needed.

Wheel bearing would be my guess. Had the same symptoms on mine and wheel bearing did the trick

A good way to isolate the problem is to jack up the back of the car (both sides), put it in neutral, leave the parking brake off, and rotate the wheel as you listen carefully to the source of the noise.

Another thing you can do while the back end is up in the air is grab the wheel and pull one side and then the other toward you, then the top of the tire and the bottom of the tire. If there's play and slop in the wheel, it's a wheel bearing.

Wheel bearing and/or broken axle.

Don't rule out a broken axle. Fairly common if you hit a NYC pothole...



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My money would be on the indy that put it as the right rear wheel bearing. Mine went out at 21,000 miles last year. Independent was $400 per wheel. I bought the wheel bearing from Sunset Porsche for $57.16 each plus $5.15 each for the lock nuts.

Good luck and keep us posted.

Thanks for all the responses. One weird thing is that the shop that stated it's some bearing in the differential actually put the car on the lift and put in "drive" at various speed while 2 other people were underneath the car to hear which side the noise is coming from (with mechanics stethoscope). Their conclusion were the noise is coming from the center near differential.

Based from the noise change from left & right sweeping motion, I'm just going to replace the passenger rear bearing first and go from there.

So I had the rear passenger side wheel bearing replaced yesterday and now the noise is gone! I really drove the car today and for the very first time since I bought the car 5 months ago I can now hear the true Porsche engine/exhaust noted :D

I took a look at the failed bearing and it doesn't look that bad inside (even the mechanic agreed) but nevertheless it was making that loud road noise. Now I feel the car drives smoother and at the same time more powerful for some reason... Oh wait... forgot I also installed JD's Spirit of Ecstasy today... (maybe that's the real reason)! :cheers:

yippee! glad it's fixed and it wasn't the diff:eek: