[masraum]

4 cyl or 6? Was it the sound of something banging/clanking/thudding metal on metal, or was it more of a scrappy noise. Did you notice anything else besides the noise? Did the power or power delivery change?

Usually by the time the waterpump is scraping or banging, you've lost all of your antifreeze. Any leaking?

Pretty much any type of engine problem can happen suddenly, but it seems less likely that a crank or rod bearing would go that quickly.

Is there oil in the car? Drain the oil, is it weird, nasty, full of metal filings? Is the pulley on the front of the waterpump loose or wobbly?

Could it be an exhaust problem?