My 2000 4.7 is making a squealing noise when I start it from cold. Its not very loud and it sounds more metallic than a slipping drive belt. If I kneel in front of the truck, it gets a little louder the lower I go. It only seems to do it cold. I'm thinking water-pump over alternator or power-steering, its done 105K (miles).

Thanks.

 

Check your tensioner pulley too.

 

It could be one of your idler pulleys or the belt tensioner they need replacing often.

Pull the belt off when cold and spin everything if anything is stiff that's the culprit like my power steering pump bearings had dried up and was binding if you tried to spin it by hand it wouldn't spin easily like it should

idler pulleys dry up and need replacing often and just spinning them is hard to tell if they are dry they are a hard call but a cheap replacement. Actually if they spin real easy that means they are dry as if lubed the lube will make them not spin easy kind of backwards compared to the other things like the power steering pump.

 

Take your belt off and spin all the pulleys and see if any are loose/grinding. Its most likely the idler.