Bad bearing(?) noise when revved too high, Then goes away... Options

[senick]

Well, just seeing what you guys think. For the past few months I've had an odd issue. If I really floor it on takeoff, accelerate very rapidly or otherwise get the RPMs up too high, the next time I turn my car on I get a grinding noise under the hood from the passenger side of the engine bay. I figure it's a bearing somewhere, but not sure. After I drive a little bit, maybe a day or two (or sometimes less), the noise will just go away and won't come back. All I can hear now is some belt squeal when the engine warms up.
What kind of a noise just goes away on its own?

[senick]

Yeah, which is why this is a bit of a head scratcher. If the noise comes back I'll get a recording of it. Also, it goes away while driving, not when turned off. Like I'll be idling and then CLICK noise gone. And it'll come back with a heavy enough foot. But, I don't like to test it... On a somewhat related note, the serpentine belt on the 7a is fairly simple to change? Is there an adjuster nut on the alternator or something?