Need help pls....01 xterra making whinning noise in mornings---

[Xterra01]

I have a 2001 nissan xterra. It has started making a funny whining noise in the mornings, and will stop after about 10-15 mins when the car has warmed up. It seems to get louder when i accelerate up until the point I pass 30mph and it seems to die down, but when I come to a stop sign the noise is back until it eventually it stops(10-15 mins later) Doesnt happen everyday, but seems to be more common than not. Also, never noticed this until the morning after it came back from the shop---it had blown head gaskets so they fixed that, resurfaced heads, put in new thermostat and heater hose. Sorry for such the long post, only had the xterra since november and have already put $2000 into fixing it...getting frustrated =(

[RT]

belt noise they need tightening or replacing just did this on my hardbody. is always in morning and on rainy days and cold days it is probably worse. BELTS squealing cause they are slipping

[Desert Rat]

Is it belt squeal?

Could also be a an idler pulley going bad. That happens too.

[Big-Bird]

The idler pulleys, there are 2 of them, both on the 4 cylinder and V6 engines can be rebuilt for a fraction of a new one. The bearings are made by SK bearings and are under $10.00. A new pulley is closer to $100.00

1) Loosen or remove the belts and check for proper movement of the idler pulleys and other components IE: Alternator, power steering pump etc. Do they move freely? NOTE: The alternator on the V6 is susceptible to damage because it is located so low in the engine bay. It's bearings can go bad with no warning.2) Inspect the belts for wear, cracks, splits &/or missing rubber ribs3) Replace the belts as needed and adjust for proper tension.

[Xterra01]

Thanks for all the help...I think it may be my power steering pump. The noise changes when i turn my wheel. Is there anyway to check if its the pump or maybe just a filter or seals? I dont want to spend $150 on a PS pump if i just need a $20 filter =) Anyway, thank you again for all the advice