GravityKnight

iTrader: (3)

this one has been puzzling me for a while. Only when good and warm does it show up. Only hear right at idle, (it's doing it above idle but its hard to hear) It's fairly loud.. Nothing obviously wrong and hard to pin point. Coming from adj cam gear area, or possibly more towards alternator. I just put a new alt on a couple thousand miles ago... I just installed the cams and gears about 1000 miles ago... Timing belt, idler etc is all new (4-5k miles).

*not and exhaust leak... more metallic sounding in person than exhaust

Just weird....

GravityKnight

iTrader: (3)

I believe I have solved the mystery. I'll post the results in case someone else ever experiences something similar.

Turns out it's the fidanza cam gears / and or belt making the noise. When the gears and belt finally reach "full temp" (actually hard to get this to happen unless you drive the car). They make noise.. the reason I know this.. if I spray water with a spray bottle on the gears and cool them off, the sound will go away.

I did this 3 times, and every time, after spraying them lightly for a little while taking the heat out of them, the sound would get quieter, and then go away.. and remain away for a while until they warmed back up. Not exactly sure what it is about them being hot that causes the sound, I know belts like this can make noise because they both displace the air as the teeth grab, and pull a vacuum as they let go.

Perhaps as the gears warm up, and every so slightly grow, the fit between the teeth and belt becomes just right.

But I feel much better as I was getting close to tearing into things and looking for bad parts somewhere.