Power Steering

Hi.....my 2001 Pontiac Sunfire has started to make a whirring humming noise......also once while parking the steering wheel made a strange noise.......I took it in for an oil change.....all fluids were okay......mechanic said sometimes these cars make noise......I'm not buying that......is my power steering pump going? How can that be tested?

Thanks

Probably is the P-S pump. Take it out and plug off the resavoir and drive it with man power, then hook it back up after you clean the pump. See what's going on. That is what I did with my old car, after cleaning the pump it seemed to be ok.