95 Mustang Squeek on Start

I have a V6 95' mustang. it does this loud squeek on every start up, than quits as the engine runs. I think its the power steering pump, cause me and my father drained the pump because the fluid looked nasty and watered up. so we drained it completely, and ran the pump for a few seconds dry. than filled the pump back up with fluid and it still looked nasty. and thats when the squeeking start, or around that time. the squeek sounds like its coming from the driver side, and my father says he hears it from the top end. he knows very lil about new cars, (mopar guy) and doesnt know. so if you have any ideas on what it is, please reply.
thank you