Engine whirring noise

Hey guys, I'm having to track down the source of this sound hopefully ya'll can help. It's like a low squeal or whirring sound. It's not the belts or brakes. water pump/ timing was replaced about 20k miles ago. The sound happens at start up in gear and out of gear, driving and parked. It seems to be louder when the truck is just started up after being parked for a few hours.

Truck is an 02 3.4L with 220,000 miles

Thanks guys

 

Power steering pump? Is your power steering fluid bubbly?

 

Could be one of the idler pulleys for the timing belt.
I had about the same noise and replaced both idlers &
water pump and timing belt all while I was in there.

 

Should be one of the two already mentioned. PS pump or idler pulley

 

Power steering fluid looks normal. It shouldn't be a timing belt idler pulley since they have only about 20k miles on them. But I guess it could be either.

It has warmed up here the past day and a half and since it has warmed up I haven't heard the noise.

 

Could still be the pump even though the fluid looks good. Wasn't there a problem with the first gens with some screen in the reservoirs getting clogged and starving the pump for fluid??

 

Check out these threads.
http://www.tacomaworld.com/forum/1st-gen-tacomas/56442-power-steering-problems-whining-pump.html
http://www.tacomaworld.com/forum/1st-gen-tacomas/305670-how-clean-3-4l-ps-reservoir-screen.html

 

My truck does that. It's the power steering, in my case. It's inaudible when it gets above 50, but any lower, and I get an ugly squealing. But my fluid still looks fine, too.