After reinstalling the A/C compressor (changed coil/clutch/pulley) I'm getting this new chirping noise when the engine is cold. The noise doesn't happen at first, but takes about a minute before it starts. Then, it goes away after a couple of minutes as it warms up. Turning on the A/C doesn't make a difference. Everything seems to be spinning fine. The mark for belt tensioner is right in the middle of the range. A/C clutch plate was torqued correctly. Not sure if it's a pulley or what. All the pulleys are: Power steering, A/C, water pump, alternator, belt tensioner idler, and crank. In lieu of a stethoscope, I used a section of heater hose to my ear and put the other end on the bodies of the power steering, alternator, and on face of the A/C clutch and didn't hear the noise coming specifically through the hose. I also tried to put the end of the hose on the nut for the tensioner pulley and didn't hear anything either. I was trying to do the same with the water pump when the noise went away, presumably because of warming up?

EDIT: If I spray water on the ribbed side of the belt, the chirping instantly goes away for a moment then comes back. Squirt water again and the noise goes away again.

Here's a short video so you can hear the sound. Sounds like crickets. Anybody have this happen to them before or know if there's a common cause?

 

Try a new belt, which aren't very expensive. It may be due to the belt.

 

Ensure proper adjustment as well.

 

Just replaced the belt and that did get rid of the chirping sound. The indicator arrow is very near the center of the acceptable range on the tensioner. Is the tensioner supposed to wiggle just a little bit with the engine running? It doesn't make any noise.

 

With the car idling, if the pointer on the auto-tensioner moves or fluctuates alot when the car is on; the auto-tensioner needs to be replaced. If the auto-tensioner made abnormal noises, it should also be replaced.

 

Here's a short video of the slight movement. I'm not sure if this is considered normal or not. I drew a black line on both sides of the tensioner to help with observing the movement. You can see the arrow is pointing just a bit off of the middle of the normal range. Again, this is with a new belt (which did make the chirping noise go away). I added more light about 11 seconds into the video, which makes it easier to see.

What do you think?

 

That is still okay.

 

Great, thank you for responding.