I'm actually not expecting a solution (you'll understand why), but I'm curious if anyone else has/had something similar.

It's a 01 996 C4 with the full taco-wing aero kit (wing, skirts, and lip) and we've had it since new and it's always been parked outside.

Whenever it's been cold soaked (e.g. parked overnight) in sub-35f temps we get a grinding/rubbing sound from the front end when we back it up and turn to the right. It will only do it that once for the day until it has cold soaked again (actually in sub-15 weather it only takes a few hours to "reset"). This started on it's first cold day (about 8-10 months old at that point). Back it up to the left and there is no noise. Pull it forward either direction and there is no noise.

For the first few years our dealer could never reproduce this issue (never sure how since it happens every time), but they attacked it anyway (which is why I said I would have another Porsche if I ever got the chance as they clearly stand behind their product). Finally we had the tech take it home for a long cold weekend and he reproduced it consistently, but still never could identify what is causing it.

In their attempts to solve the problem (without being able to reproduce it) they entirely replaced the following:

• Steering rack and power steering system.
• ABS system (pump, front lines, front calipers, sending units, etc..).
• Front suspension and control arms.
• Front drive system (diff, axels, and hubs).

Basically everything mechanical from the cabin forward was replaced in the first couple of years trying to correct the issue.

My wife and I differ a bit on our descriptions. I think it is coming from the right side, she thinks it's more centered. I think it is more of a feel than a sound (which I think is born out by not hearing anything from outside the car). I think it is more of a plastic/rubber sound (kind like a piece of hard plastic rubbing the treads of a tire), she thinks it's more of a metallic sound.

PASM and the AWD system function flawlessly and there has never been any drive train issue (other than a couple of RMS replacements) with it.

Anyone else experience anything like this?

 

My guesses include a bad wheel bearing or a front differential bearing, but it sounds like you've addressed those issues.

 

Omg. Your parking outside in -35f. Thats really cold. Maybe its froze up parts. Thats way too cold to be out.

 

You won't find me anywhere that cold. That is a hyphen, not a negative

 

Wheel bearing?

 

I'm experiencing something similar although mine seems to be getting progressively worse. I'm also getting a lot of "road noise" at freeway speeds. I don't get any play when pulling/pushing on the wheel but I'm thinking wheel bearing for both of us.

 

This is a case for Click & Clack.

 

Except in my case the wheel bearings were already replaced and the issue continued on the next cold day a few weeks later. I would also expect additional issues (like you seem to be experiencing) rather than it being limited to just a very specific case (maybe not in the short term, but certainly over 12 years).

Good luck with yours. I had something similar with one of my old BMW AWDs and it turned out to be a bad axle on the front passenger side (had previously been wrecked and badly repaired which included reusing the axle which had been slightly bent).

 

Oh, I didn't catch that you already had the bearings replaced. That is definitely strange...

 

I have the same noises, but at slow speed when turning. Brutal metal-about-to-break sounds. Hand on shifter; feels like the front diff will snap !

184000 C4S 993

 

Interesting that I just had this happen to me for the first time the other day (a very cold day). Came out of work and backed out of a parking spot while turning the wheel to the right. I heard what sounded like a scraping sound so I stopped, got out and looked things over, but didn't see anything obvious. It has not happened since (though I haven't had the car out in the cold again), and it definitely never happened prior to that.