2000 Malibu LS, LOUD grinding sound from engine

Two days ago my car made a loud, obnoxius grinding sound when turning, then the noise stopped. I started it up today and it now makes the loud, obnoxious grinding sound nonstop, in park, drive etc, making it undriveable to the service shop. I cannot at all pinpoint the location of this sound in my engine. Any advice? HELP!!:uhoh:

1) Starter sticking?
2) Valves loose (loose rockers)

You need to pinpoint the general location of the sound and reply.

I'll try to find the origin and reply. Thanks for the help!

1) Starter sticking?
2) Valves loose (loose rockers)

You need to pinpoint the general location of the sound and reply.
I started her up again and this time no noise. It did make a quick grinding sound as if I turned the key when it was already started. It has typically only made this noise long after running for awhile and gone away quickly, so could it still be a starter problem?

Tensioner bearing,Alt bearing,PSPump bearing,A/C clutch and/or bearing.

I agree with twisted. Check the A/C compressor clutch for little bits of metal shavings. If you see them, the AC pulley bearing has failed and you need a new compressor or compressor clutch and pulley. Very common issue on these cars. If the noise quiets down or goes away when the A/C is on, and gets louder when you turn the A/C off, it's definitely the compressor.