jenskleis

Hi guys,

My car was in for a service (oil and brake-fluid change + new front brakepads) recently.

Since getting the service, the car has begun to emit an odd noise when going approx 100 km/h and above.

The noise, which is coming from somewhere in the rear, is barely audible, but it is there. Certainly there enough to annoy me out of my mind.

It sounds as if something is flapping in the wind. Not a metallic noise, but more like rubber or some other soft material vibrating.

I have looked inside the rear wheel arches, and in the engine bay, but I can't see anything loose.

I have also tried to lower and raise the spoiler at the speed, when the noise begins, and it seems that the spoiler does not have any influence on the nose. (I have a RUF module, so I can test the car with the spoiler down at speeds up to1 130 km/h)

I wonder whether a panel underneath the car is flapping. Maybe the engine under-tray?

What do you think? Any ideas?

I am going to Nuerburgring for a Porsche event on the weekend, and can not bear the thought of spending two full days on the Autobahn listening to the bloody vibrating noise.

Take care,

Jens

TheOtherEric

My money is on loose lug nuts.

MarkD

I am going to gamble on a loose/incorrectly installed fender liner... pass side, rear.

really hard to diagnose online, of course.
Could also be an incorrectly installed under tray, as you suggested.
Good luck sorting it out!

jenskleis

Hey Eric,

Many thanks for the suggestion.

I just checked all lug nuts with a torque-wrench. They were all perfectly tightened. :-(

jenskleis

@ Mark,

Very interesting suggestion. Judging from the noise, I already thought about the passenger side, rear fender liner.

I just tried to poke it 5 min ago, when checking the lug nuts, and it does seem to be loose.

But, I can't really figure out how it is supposed to sit, when fitted correctly.

tigerrat

The spoiler wall could be a possibility. Ken

MarkD

it is a bit fiddly... the rear liner half slips under the forward fender liner half.
There are 2 captured nuts on the forward piece that the screws attach to.
Those two top screws are normally not removed for an oil change.

The front edge of the forward liner half is where things are removed during an oil change.
It is hard to describe but there are pics on Mike's DIY site here: http://www.pcarworkshop.com/index.ph...the_engine_oil

Not sure if that helps or where it is loose...

Are all of the rocker panel screws there?
Just a thought.

95_993

+1

NC TRACKRAT

Take it back to whoever did the service and make them put it up on a lift, remove the rt. rear wheel and inspect the wheel well liner to ensure that it's on correctly. Also the rt. rocker panel and small cover plate. Are the engine and transmission underbody trays still installed? If so, check to see if they're properly fastened.

IXLR8

I know the noise...it was driving me nuts last week.

Well look again, only this time, take your hand and lightly tap the top portion of the fender liner upwards where the screws join the front and rear halves.

Its the speed nut making contact with the fender. There is a metal tab on it to prevent the point of the screw contacting the fender. That tab is what makes the noise.

I placed a 1.25" square closed cell (so that it does not absorb water) foam pad on the inside of the fender where the tab makes contact. Clean the area before applying the self adhesive pad. I used pick-up cap foam tape (3/16" thick x 1.25" wide).

jenskleis

Hi guys,

Many thanks for the suggestions.

Re the spoiler wall, already checked it and it is in perfect nick.

I have tried to tap the the rear wheel arch liner (passenger side), as Alex suggested, and it does make a noise as if something is hitting the inside of the fender.

So, this afternoon I will try to take off the wheel and have a good root around the inside. With the car on a jack, I will also check that the engine under-tray is properly attached.

Fingers crossed that I will find a solution, as I will hit the road to Germany tomorrow!

By the way, the wrench who did the service is on holidays. Otherwise I would have taken the car right back to him.

I will let you know what happened this afternoon...

Take care,

Jens

matt777

I had this exact problem after forgetting to put all of the screws back in. The line just starts flapping at speed.

IXLR8

Just by lifting the right rear, I was able to get to the two screws at the top of the fender liner that join the front and back halves.

The plastic fender liner is quite pliable and deflects easily enough that you will be able to see a very faint mark where that speed nut makes contact...good to get to it before it wears through the paint.

Once you apply the closed cell foam pad and button it all up, tapping the fender liner thereafter will result in no noise at all. In fact, the metal tab will end up resting against the foam pad.

jenskleis

Problem solved!

You were spot-on about the screw tap inside the fender liner.

I have now protected the offending screws with adhesive protection foam on both passenger and driver side.

After a brisk test-run, I conclude that the noise is gone... and I'm ready to hit the Autobahn tomorrow :-)

Thank you all for your help!!!

Take care,

Jens

IXLR8

And I know why mine was making noise.

There are 4 screws and 2 plastic nuts holding the forward fender liner in place.

The 2 screws holding the front and rear halves of the fender liner together should be the shorter of the 4 screws. The longer ones are used at the bottom front of the fender liner. There isn't much of a difference between them but I had their locations reversed.