Buzzing noise from engine bay @ certain RPM
 

Not sure if this is normal or not - so I thought I would ask.

My '07 8 has about 2000 km on it. I noticed this sound right after break-in was completed and I started reving the motor, and pushing the car a bit.

I hear a light metalic buzzing noise coming from the engine bay. It sounds like there is something vibrating. One of those noises that if you put your hand on the vibrating object, it would stop.

This noise can't be reproduced by reving the engine in neutral, or slowly bringing the car up to speed - it requires load on the car for it to happen, as if it may be suspension related.

Under medium to hard acceleration, the noise starts at 6K, lasts for maybe 500rpm, then goes away. It then restarts around 7500/8K and lasts through to redline.

Sounds to me like there is just something in there that needs to be tightened up - but I thought I would see if anyone experienced a similar noise that ended up being related to the engine (which is my concern).

I have something that sounds a lot like this with mine, which is an 05 with 12k miles. Oddly, I get the same kind of rattling, during acceleration, only under load, and ONLY when the car is cold. Not reproducable with the car in neutral. Only thing is, my car does it at lower RPMs, not higher like yours. Drivin' me nuts...

I don't rev my car when it's cold - but temp does not seem to be a factor. Does your noise seem to come from deep within the engine bay?

I've got something like this. Mine is at high rpm and usually when its cold outside. I think this could be the TSB for a rattle under the cowl. Check to see if this TSB applies to your car.

Mine did this.. it turned out to be a loose heat shield on my aftermarket cat. If you have any aftermarket parts, check them.

I started hearing a rattle after replacing the cat with a midpipe...starts at 4k...goes away...comes back at 7-8k...

Very annoying...it sounded like something metallic vibrating against something else...the only thing I am thinking is that its perhaps the factory cat-back...but since it does not really happen when in neutral its hard to pinpoint driving while the windows are down...

I'd say reguardles sof aftermarket or not, this is a possibility. It is likely something that wasn't quite tightened down initially. I've had problems with those heat shields over the cat in numerous cars. It can be a HUGE pita.

and it's an 07 you say? Heck...drop that sucker off at the dealer. Their problem then...not yours.

Look for something loose under da hood.

Exactly what I've had for a couple years. Welcome to the marbles club!

It's the intake manifold's opening of fuel valves...3rd injectors come on around 7300. It ruins the sound of hitting redline a bit, but my new MS exhaust seems to have cancelled it out enough for me to stop caring.

Search, it's normal, and dealerships aren't going to fix it.

Reviving this thread (from a search), I've been experiencing the same problem recently, seems to be around 3000-4000 rpm, definite metal rattling, for those who have had this problem, was it the heat shield? Going to take it in soon to have it checked out. Thanks guys!

Check your engine mounts. A cracked one will vibrate.

It's going into the dealership next week to take a look. They seem to think it is the heat shield. This is not a "marble" sound.

If you're hearing the rattle with a sunroof open, be sure to confirm that it's actually the ENGINE rattling and not the sunroof. 04/05's have been synonymous with the rattling sunroof, which was even finally offered a TSB.

Just a thought.

You've got marbles! Search...there is a fix!