Winter Rattling Normal?

[scaumster]

Hearing a rattling sound from what seems to be underneath the car. Took it to a mechanic a week back for a bumper to bumper check and he okayed it (I am a new 02 P5 owner) I heard that this model will do that in the winter after being left for say 10 hours parked inn the cold (-8 where I'm from.) When I start the car and begin to charge off in it it seems to have this shake/rattle almost as if something is loose like my muffler. When it has been running for a while 15mins or more the sound will disappear. Any ideas?

-Worried P5 owner

 

[SIBalla23]

No worries. My car does the same thing in the winter. It rattles and makes noises when its really cold and not warmed up. I think every car does that. Plus you said someone checked it out and said it was fine, so I wouldn't worry. I see your a new member to the forum too, so let me welcome you to this little protege community. Any other questions feel free to ask and you should get what your looking for.

 

[Rusty]

Yep, it's been covered. The noise is caused by turbulence when the VTCS butterflies are closed before the engine is warm. VTCS (variable tumble control system) is a set of butterfly plates in the intake manifold that close to rich up the fuel-air mixture and heat the cat up quickly. After the engine reaches 140F it stays open.

Some people (I think mostly '03s) have had screws come out of the butterfly plates and get sucked into the engine. There are plenty of horror stories about this and the VICS butterfly screws too (also in the intake, but for high rev performance).