Strange noise, like a can of coins, from engine compartment

If the cat converter is broke apart inside,,you should be able to hit it and make the sound. The first generation cats when the whole emmision thing went down(79ish?) would break apart inside pretty easy,,now days,,more rare to have one come apart inside. Not saying it couldn't happen,,just rare.

Any of your bolts that you loosened come loose after your master/slave cylinder work?. Did you loosen any other bolts to move something out of the way as you did the work?. Could still be a clutch issue. A intermittent slipping/shuddering clutch can create some very strange noises.

 

When my clutch went bad, I had a similar noise to that. It ended up being the pilot bearing being seized up.

 

My 99 did that around 200k miles. Ended up being the front O2 sensor, nuts had rusted off and the whole thing was rattling.

 

That's hardcore bad. A chance of galling the end of the input shaft off,,then bigger bucks. When I do a clutch I do the whole thing minus the slave and clutch master cyl if they don't need it. Been down the "should have" road a time to many.

 

I have a similar noise occuring at freeway speeds. It's like a rustling sound. I keep thinking it's something on the firewall shaking around from wind or something, but I have yet to check.