whinning noise

ive noticed a whinning noise coming from the left side of my 1996 sc2 5 spd. its got 136,000 miles. the mechanic that just changed the power steering pump thought it was something in the valve train, i forget what he said, whatever it is on the left side just under the valve cover. i heard a lot of u guys mention idler pullies making noise, is this part in the same area? whats it look like? any other ideas? any help is appreciated.

I had a whine on my '94 SL2 129K. It turned out to be the alternator. $85 aftermarket and several hours. Had to pull the power steering pump up out of the way and take the alternator out through the wheel well.