Water Pump/Alternator Noise?

I was using the TO-20 with finish mower yesterday, and about 10 minutes in, I heard a screeching/grating/metal-on-metal noise from the front end of the tractor.

I headed back to the garage, and turned off the engine, while I grabbed a "listening stick" to try to pinpoint the source of the noise.

When I restarted the engine, the noise was gone, and didn't return, after a few minutes of idling, and varying the throttle.

Based of what I've read here, I suspect either the water pump (I haven't touched it in the 5 years I've had the tractor), or the alternator (12 volt conversion with one-wire alternator, done by previous owner).

When I turned off the key, as the engine was stopping, I could clearly hear the "metal-on-metal" noise, like a bad bearing/bushing, but the noise was gone when I started it back up.

I've read how to narrow it down to the water pump or alternator, by removing the fan belt, but first I need to get the noise to return.

Can water pump or alternator noise be intermittent? Am I damaging something by running the tractor, until I can figure out what's going on?

Oil pressure was good, and temperature gauge was normal.

Thanks for any ideas.

is it possible the "fan" belt is too tight?

is the water pump weep hole weeping?

next time it makes noise carefully put your hand on alt. sometimes you can "feel" the bearings. would not try that with water pump.

good luck.

Remove the belt and turn the fan by hand, paying close attention to any "off feel", then do the same for the alternator. A bad bearing may feel a little rough helping you to pinpoint the problem. Make sure to try rotating both ways.

While you are there, feel for slack in the crank pulley, be sure the bolt is not loose.

And some have very little clearance between the fan and the shroud. Look for evidence of that hitting, could also be an indicator of water pump bearings getting loose.

Thanks to everyone for the ideas. I'll see what I can find, and report back.

I read about the water pump weep hole in the Shop Manual, but I couldn't find it - where is it? (I don't seem to be losing coolant anywhere.)

bottom of pump.

Update: Belt tension was good, crank pulley bolt was tight, and water pump and alternator both felt good when I turned them by hand.

As I was checking the alternator and adjusting the belt, I noticed that if everything wasn't lined up exactly right, the alternator cooling fan fins could rub on the mounting bracket, which would produce the kind of noise I heard.

I suppose the alternator and/or bracket could have shifted a little and caused the noise? Still don't know why it stopped, though.

I'll keep an eye on it. Thanks again for the help.