2004 Ford Explorer

Could be power steering pump or low fluid, or could be belt slipping, or could be bearing in a/c compressor. or could be bearing in alternator going bad, or could be cat stuck....Take the belt off and run it for 20 seconds, did the noise stop? that should narrow it down....

im hoping for the cat

AC clutch

Thank you all so much will check into both answers.

you can take a solid rod...like a large screwdriver or ratchet extension and just touch all of the loads under the hood, like pumps, compressor, etc while holding the rod to your ear.....works like a stethoscope you can identify the cause or select area

After cranking my truck up and youtubing what it sound like when a ac clutch go out I believe that it is the issue. Its dark here now but will have it looked at tomorrow to see if that needs to be replaced thank you so much.

lucky guess on my part

Very good guess it was

With a spray can of penetrating oil, you should be able to eliminate each item one at a time. Just hit each pulley with one or two drops of the oil. The correct one should stop the noise in seconds, but only for a few minuets. Look at each pulley. If it has grooves in it, it is turning a functioning part like an alternator, water pump or something like that. If it is smooth, it is an idler pulley. Just there to help routing of the belt. Idler pulleys have a sealed bearing they spin on. These will squeak on occasion. The oil will help ID the one. Alternators also have sealed bearings in them. These are harder to get oil to, and therefor harder to determine if bad. But here the long rod or screwdriver will help as the alternator is large enough to do this more safely. Water pumps have sealed bearings in them also, but because there is a ceramic seal behind that bearing, if it gets loose, it will usually leak water also. Power steering pumps are internally lubricated. If they are full, they should be quiet. A/C compressors have a large bearing that the pulley rotates on all the time. If that bearing gets noisy, the oil will ID it, but is harder to get at to spray. An A/C compressor can also be noisy internally, but not usually a squeaky noise. I hope this helps.