I have been searching for an answer from this site for (how to figure out)where a chirping sound is coming from underneath my engine hood.


I am not a mechanic and I do not often post on this site, but I think it was important to post this one time.


I parked my car one cold morning and when I started it up, it sounded like I had a chirping bird under somewhere under my hood. When the car warmed up, I noticed the chirping sound would lessen and often go away. I changed the serpentine belt, but the noise kept on. After reading various posts, I changed out the idler tension pulley and several drive pulleys (bearings, not the actual pulleys cause members gave me the correct bearing numbers to buy them and press them out). I then cleaned the serpentine belt and all the pulleys with brake cleaner and a soft Bissell brush, but noise was still there.


When I took off the serpentine belt to check the rest of the pulley's for wobble, I noticed my alternator was chirping also so I changed it thinking that the bearing was bad. Unfortunately, this slowed the problem, but did not fix it.


One of the members said that it might be an ac clutch bearing and to check it by pressing in the a/c button. If the noise stops, then it is the bearing on the a/c clutch.


I then bough the stethoscope from Harbor Freight to try to locate the chirp, but every time I got near the engine compartment, the chirp would go away.


Well, this did not fix the problem either.


I finally read a random post by a member who said to check the fan clutch bearing. I read up on how the fan clutch works, and how to diagnose a bad one. Everything I read showed me that I had a good fan clutch. Regardless, I took off the fan clutch and ran the car for about 2 minutes without the fan shroud, fan blade, or fan clutch and the noise was gone.


I then put the fan clutch on a vice and tried to spin it as fast as I could. Sounded like the bearings were going bad in one spot every time it went around, but I could not get it fast enough to get it to chirp.


I replaced the fan clutch about a month ago and the noise has not come back yet.


Just a though for everyone before spending tons of money on trying to find their chirp under the engine.

 

Welcome to the forum and thanks for the info.