Help! High-pitch squeal/chirp coming from engine.

[TylerDarby]

Hello, everyone. I drive a 1998 Ford Explorer XLT.

For the past few months, there has been a high pitched squeak/squeal that comes from the engine. It's a "chirp" that has a rhythm, and as I press on the accelerator, the chirp gets faster and faster. It is loudest as soon as the car starts, and eventually gets quieter/less frequent (but sometimes doesn't stop at all).

We've taken it to the shop twice, they've replaced the belt itself and most parts connected to the belt (tensioner, alternator, idler) and nothing has changed.

I still believe that it is the belt or a connected part, however, because when the chirping is happening, I can pop the hood and spray a bit of water from a hose pipe on the belt, and it will stop for a few minutes and then start again (I assume when the water dries).

This noise is beginning to drive me crazy! Please help!

 

[koda2000]

Which engine - If it's a V8 it could be the cam synchronizer. Pretty common on the 5.0 V8. I have one that's making a chirping noise. I removed the sensor from the top and put in about 20cc's of transmission oil to shut it up. That was about 2 weeks ago and it's still quite. I'm trying to put off replacing the synchronizer until warmer weather.

The SOHC V6 doesn't suffer from the synchronizer noise, but the OHV V6 might. I don't know.

If it's not the synchronizer it might be a worn out pulley bearing. Remove the serpentine belt and run the engine for a minute to see if the noise goes away. If it does it's a pulley bearing. Spin the various pulleys by hand and listen and see how they feel.

I verified that my noise was coming from the cam synchronizer using a mechanics stethoscope. As soon as I put the tip on top of the sensor I could hear the noise clearly.

 

[swshawaii]

4.0 Harmonic Balancer - know when it's going bad & how to fix
http://www.explorerforum.com/forums/showthread.php?t=302068

 

[Flash]

The A/C clutch on my SOHC makes noise but I wouldn't describe it as a chirp.

 

[Rhett]

It's probably the cam synchronizer. Common on the OHV V6 and 5.0L V8's.

Word of warning - It's not easy to get to on the OHV V6.

 

[Rhett]

I verified that my noise was coming from the cam synchronizer using a mechanics stethoscope. As soon as I put the tip on top of the sensor I could hear the noise clearly.

OP. On the OHV V6 the cam synchronizer is located on the back of the block, right next to the firewall.

 

[1998Exp]

Got to love all these speculations, when the OP did not even bother to tell what engine he has!
Edit: just noticed it's his first post. He's probably not even aware that there was more than one engine available.

OP. On the OHV V6 the cam synchronizer is located on the back of the block, right next to the firewall.

 

[TylerDarby]

Got to love all these speculations, when the OP did not even bother to tell what engine he has!
Edit: just noticed it's his first post. He's probably not even aware that there was more than one engine available.

I'm aware that there's more than one type of engine, I just forgot to mention it.

I have the 4.0L SOHC V6.

 

[koda2000]

I'm aware that there's more than one type of engine, I just forgot to mention it.

I have the 4.0L SOHC V6.

Then the noise is not the cam synchronizer. Like I said earlier, remove the serpentine belt and run the engine for a minute and see if the noise goes away. If so it's belt, tensioner or pulley related. If you don't do your own work and your mechanic can't figure it out, find another mechanic.