[p5150]

I had a sound that was bothering me as well - it sounded like a metal grinding noise - almost like when you crash engage a starter but slower. But it only lasted a few seconds so I attributed it to a ps pump or ac compressor...... Who knows.

Its not your piston slapping your cyl head so calm down. If that was the case your car wouldnt run.

Ill go with mdr40z and guess piston slap.