Unknown noise

[andrewg29]

It's a 2002 Chevrolet Tahoe z71 and when It has been sitting for over night in the morning when I crank it, it makes a mixture of a squealing and a grinding noise that sounds like it's coming from the front passenger side of the truck. It also does it when it's raining outside. Once the engine warms up to about 185 degree the squealing stops and won't do it until the next morning. It also won't make the noise when the truck has been sitting out in the sun. Any help is greatly appreciated!

 

[Tony7781]

It's a 2002 Chevrolet Tahoe z71 and when It has been sitting for over night in the morning when I crank it, it makes a mixture of a squealing and a grinding noise that sounds like it's coming from the front passenger side of the truck. It also does it when it's raining outside. Once the engine warms up to about 185 degree the squealing stops and won't do it until the next morning. It also won't make the noise when the truck has been sitting out in the sun. Any help is greatly appreciated!

I have a 2003 Z71 and mine does it every now and then on the first start up. It only lasts for a few seconds and goes away. Im in to see if anyone has any ideas on what this could be?

 

[M Hankel]

Hard to diagnose these things without hearing it in person. Few things it could be:

-A/C pump, mine is going out and it makes a very obnoxiously loud clicking noise when it tries to engage the drive clutch with the A/C or defrost.
-Front drive belt tensioner pulley bearing
-Water pump bearing
-Alternator
-PS Pump

Inside cab, fan blower motor? My GF's Tahoe has one that is going out and it howls like crazy for the first few minutes its on.