scratching noise from the front

[nnz1398]

My wife has a brand new 2006 2.5L Auto NB for a little more than 2 months. In the morning after car starts, there will be a high pitching noise before the oil temperature warm. That is common according to everybody's experience. However after that start noise faded, and the car is driven at near 20 m/h with gas pedal pressed, there is a scratching noise from the front. The noise is not very loud. It sounds like bushes scratch the bottom of engine compartment. But the car is driving on perfect pavement. The noise will last for 3~5 minutes. Then it is gone.

We brought the NB back to the dealership. They changed the drive shaft, saying that the shaft was not symmetrical as it should be. But noise didn't go away. We brought the NB back for the 2nd time. They secured the heater shield. But still the noise is there. Now we can even hear it at 40 m/h.

Apparently, the dealership doesn't know what they are doing? Anybody here know what the problem is? Thanks a lot.

[Maggadog]

It's hard to track down a noise that only shows up when the car is moving, especially at 40 mph. Perhaps the spedo cable or some other cable is making the sound, or the tires need balancing/adjusting (?) especially if the noise gets louder as you go faster.

[Oyveychris]

Are you missing a cat/dog?:D

[nnz1398]

The service department of Another VW dealer, Royal VW in Orlando FL replaced the catalyst converter. The noise is a little quieter there when the gas pedal is pressed but not metalic anymore. The service manager said it is because that they didn't have a new gasket between the converter and other parts so they used the old gasket, and they will replace a new gasket once the order arrived. I doubt that a new gasket will completely kill the noise.

[Oyveychris]

Sounds as though the heat shield is rattling against the catalytic converter...

[dunno513]

I drove around for about 3 months thinking my tranny was shot, then thinking my Cat was all screwed up all because of a rattle that only occured at varied speeds.

Turned out it was a rusted off U clamp that was still attached around the exhaust pipe.

Point being... Get under the car, (you'll need some ramps, cheap at walmart) and look around. push and pull things, smack stuff lightly with a rubber mallot. It's amazing what will make noise due to the smallest issues. Sure if you don't like getting dirty, let VW do it, but don't expect perfect results.

(I'm totally willing to bet, its an issue with the clearance between the Cat heat sheild and the body. Based on similar reports, heat/time/speed change, and different results each time VW works in that area)