My 2002 Kia optima makes a screeching sound when u start it up. Lasts for 30 seconds then stops. Now its doing it when I start moving. Had a new alternator and belt replaced a few months ago. Replaced the power steering hose 1 month ago for a leak tried belt dressing but nothing has worked. What could be the problem. My mechanic said maybe a bearing in the alternator. Any ideas.

SOURCE: power steering problem, noise coming from engine, 97 montero

Your experiencing the same thing my 02 is experiencing- your crankshaft pulley is slipping on the crankshaft. It only does it under load, i.e. turning steering wheel(loads the power steering pump) running heater blower on high with headlights on (loading the alternator) or running the a/c with blower (loading the a/c compressor and alternator). Turning off all lights, blowers, ac, etc and allowing the car to idle should kill the slipping until loaded again. This problem is very serious and very expensive if your don't catch it early. It require repairs ranging from tightening the crank to pulley bolt, to replacing the pulley AND your crankshaft if it is allowed to continue. if you cannot get it serviced immediately then do your best to keep loads off of your belts by driving with the blower off, A/C off, and lights used only when necessary. Also try to avoid extreme tight turns which load your power steering pump. Your repair, if not done asap, will cost you upwards of around $3k since the motor must be removed and completely torn down to replace your crankshaft and pulley. I would seek a tech who will exhaust every other method- i.e. sleeving, welding, etc. to effect a repair. Just don't put it off because it will only get worse...