Engine sound from 4th Gen Nissan Maxima (infiniti I30) with AC/alternator belt removed. Turned out to be a bad crank pulley. Rubber center of the pulley was aged and cracked. The noise was the outer pulley ring rubbing against the power steering belt. Notice the pulley wobbling. Do not drive your car if you pulley is doing this. You risk a complete failure which could cause engine damage.
4th, Gen, Nissan, Maxima, Infiniti, I30, crank, pulley, noise, bad, 1995, 1996, 1997, 1998, 1999