Even if it was a Honda, it could be a hundred different things. Water pump? Camshaft bearings? Alternator? All we can do it guess...

One of you has to listen under the hood to narrow down the location of the noise. Put a short piece of garden hose up to your ear & listen. Then use a screwdriver held against the engine & pin-point it even better. You can't even decide whether to mess with it yourselves, until you figure this out. Even if you go to a mechanic, you'll have something to start from.

Check it out & come back with more information. Oh yeah, what kind of chevy? Somebody's bound to flame you because it's not a Honda...