I hear a moaning sound from my car, and I'm not sure what it is...

My driveway inclines down towards the street. When I exit the driveway, I must brake and turn right just before I get to the end of the driveway.

A few weeks ago, I heard an odd loud moaning sound as I did this. This sound has repeated every day since.

At first I thought it was the brakes, but I've never heard brakes make a low pitched "moaning" sound like this. Also, I just had the car serviced at the dealership, and they would have told me if my pads or rotors needed replacing. Further, I do not hear this sound when I use my brakes on local roads or highways.

This morning, I crossed a couple of speed bumps. Just after my rear tires descended from the top of the bump, I heard the moaning sound (a little shorter in duration and not as loud). The car’s speed was already low, so I did not have my foot on the brake pedal as this happened.

Now I am thinking this sound happens when the rear-end unloads (ie. the rear tire "drops" as the strut "extends"). This loading situation may be similar to the driveway scenario, where the nose dips, and the rear rises as I brake and turn. (Of course, at the low speeds, this wouldn't be visible, but I assume the suspension is still moving).

But… I am not sure if my theory is right. The sound could still be caused by breaks or other suspension components.

Does anyone have any ideas what could be causing this sound?

How could this be diagnosed or identified? (I hate when you go to the dealership and they find nothing).

 

Likely the sway bar bushings need to be lubricated.

 

Thanks for responding!
Now, I'll be armed with more info when I go to the dealership.
I'll direct them to check the sway bar bushing.

 

The steering rack can make a bizarre moaning sound if it begins to fail. Typically more noticeable when the car is cold.

 

Thanks guys.
My appoint is scheduled for next week at the dealership.
I’m hoping it’s nothing major.

 

stevepow,

You win the prize.
Unfortunately, I can't pay you, because the Porsche dealer took your prize money.

Any way, you were right; it was the steering rack.

Apparently, there was a bad seal, and fluid had started leaking into the rubber boot.

It's an expensive repair because they're replacing the entire rack.

 

Just wondering how much is the Porsche dealer charging you to fixed this issue? Apparently I have the same issue you have.

 

MIKOB,

I just got the car back yesterday. It ran me around $2500 to replace the steering gear and perform alignment.
I took advantage of a dealer's special on alignment, and the dealer gave me a small discount on the labor.
But the biggest cost reduction came from the "core return" of the damaged part, which saved me almost $600.

Question for you...

When you drive your car at highway speeds, do you visually notice or feel a minor high frequency vibration in your steering wheel?

Prior to this repair, I always assumed the vibration was due to a slightly mis-balanced wheel. It was very minor and not overly concerning, since the car was always very stable.

However, after the repair, I have pleasantly noticed that my steering wheel no longer vibrates the way it did before. I still do get road surface feedback in the steering wheel, as you would expect in a sports car, but I can kind of "feel" the difference.

I wonder if one of the symptoms of a bad steering rack is a high frequency steering wheel vibration? Is this something you've noticed, since you know you need a new steering rack?

 

I still have a slight moaning "sound" from my car, but I think there may be multiple separate issues that appear under similar situations (slow parking lot driving situations).

1. (DONE) I think the steering rack replacement addressed one part. I don't hear the sound when I turn the wheel at slow speeds. A seal on the rack was leaking, so I'm glad that this is now repaired.

2. (TBD) As soon as I left the dealer, I heard a moaning sound from my brakes. This is probably just due to oxidation on the rotors and pads. My pads have a lot of life left, the rotors look good, and the car stops on a dime, if needed. So I think I'll wait to solve problem #3, below, before I get to this.

3. (NEED HELP) I still hear a "sound" when the back-end of the car drops after going over small speed bumps, as I described in my original post. This is a very low speed scenario, and I do not use the brakes at all. Do you guys think this is bushings or something else? How can I check? This is a 2008 "S" model, with PASM, and the suspension is stock.