Squeeling coming from engine?

Bought a 1995 Ford Mustang GT a few months ago. It has 163,000 miles. The past few weeks whenever I start it up and it idles there's a squeeling sound coming from the engine bay. Once I shift it into drive and start driving it stays for maybe 10 seconds and then goes away. If I come back 10 minutes later and turn the car on the squeeling is not there anymore. I checked the belts they look fine (not wet, cracked, worn). I looked at the engine with the car running and the squeeling sounds like it is coming from a pulley in front of the alternator or pulley under the alternator. The belt is not loose either. At first the sound was faint but after a week it has become a little louder I can hear it now without putting the windows down. Sometimes it is quieter still. Even put some WD-40 to lubricate inside the pulleys and that did not work. Any idea what this might be? Does it need fixed soon?

Yeah

Don't worry about it

The belts may need to be greased or they are not allied properly.

Loose serpentine or accessory belt - DON"T grease or align! Tighten the belt, if that doesn't work you can replace the belt (gotten old a hard and slips when cold) or add a belt 'dressing' - replacing if it is due and is recommended.

You need a new belt. It should be self tensioning.

Take that belt off of there and spin& tug your pulleys. THere's pulley not turning free probably.

Our daughter just had this problem. Same sounds in her Olds. It got worse. She replace serpentine belt that how we found the problem. It might be time to replace your tensioner pulley for the serpentine belt. Yeah they can wear out. Turn car on watch the pulley area, if belt moves to much theirs your problem. Turn it off take the belt off. Take your hand put it on the tensioner pulley it moves ins & out there you go.

There's your sound. Daughter has done engine mounts, replaced many parts on her ride. This was not one of them. The sound travels under the bay of hood. It quits then starts back up later. Had same happen to 89 98 olds as well. One minute fine next turn over bad sound. Checked everything then listened close to where it was coming from. Sure enough same part. If you don't replace it & put new belt on it the tension will make things worse. The sound is louder. Yeah you can damage your engine. Check that tensioner pulley.

FAILING serpentine belt pulley! ANY oil change enter can check it for you! Get a CONTINENTAL kit instaled on there! OPEN HOOD and actualy LOOK at thigns! PWOER WASH engein bay with GUNK ORANGE cleaner to eliminate the GREASE and FLUID factor! AT thsi MILEAGE get a NEW BELT SYSTEM installed on it! BYE NOW!

The average person can't tell the difference between a slipping rubber belt squeal and a failing bearing squeal.

When you first start the engine, the alternator charges strongly for a moment. If the serpentine belt is loose or worn, it will squeal for a few seconds, or 20 seconds, or whatever, and stop. It could be an old, stretched or loose serpentine belt or improperly working spring in the belt tensioner.

But if it never stops, it could be a bad bearing in the belt tensioner pulley or a bad bearing in the iidler pulley.

Start by inspecting those items.

The bearings on the alternator are needing a touch of oil or replaced, if there's any water leaks below the engine it could be the water pump bearing could need replacing