After a 3 hour highway drive, I parked my car outside and then about 1/2 hr later restarted it to move it into the garage. I heard a rattling sound (kind of like like marbles in a can) from the engine as it sat at idle - never heard that before. By the time I had pulled into the garage it had cleared and the next day on a shorter drive, car sounded fine.

Any idea what that rattling was coming from? (it was not from the exhaust and it was louder inside the car than outside)

 

Check to see that nothing is loose in the under carriage, sounds like a vibration noise caused by something loose. Exhaust is the first thing that came to mind. I would have it checked out none the less just to be sure.

 

Sounds like a flywheel noise. Better get it checked out. The 997GT3 guys are seeing flywheel failures now

 

It is normal. The car does not have a check valve in the oil tank like the GT3 or the older TT. It is the system pressurizing again. You can get the vlave from the GT3 and update this if you would like. It is normal.

 

Hey Stephen, isn't the whole point of the dry sump system having positive pressure in the oil system before or at start-up? If he's getting valve clatter, I would say it's another example of theory not matching real observations!

 

hey i've noticed this too. when i start the car from cold, if i release the clutch immediately after starting, i hear a loud "clatter" that lasts a split second. but its loud!

however if i start it and wait say, 2 or 3 seconds before releasing the clutch, there's nothing.

could this be connected to the intermittent oil leak that the dealer said was a flywheel seal issue?

 

car seems perfectly fine, so I'll go with the PhD's answer

 

I've heard it once. Sounds like the flywheel.