Frightening squealing sound from the engine

[Helirich]

Hi there folks, this morning me and my friend sat and listened to the noise very carefully for about twenty minutes... We helped ourselves with a water hose, trying to locate the source of the noise!

The sound is definitely coming from the center / left rear side of the engine... We weren't able to perform the removal of the belt, we'll try that out another time. Regardless, our common opinion is that the noise is caused by a leak somewhere, specifically an air leak. The point is we can't locate it.

The noise occurs whenever the engine demands for air, whether at idle (the infamous hunting motion) or at low speed when the throttle is pressed. In fact it appears when the cars slows down, at turns or when it stops... At normal travelling speed the wail just isn't there. The noise is so loud that it freaks everybody out!

We plan to dedicate some more hours to search and analysis... Any further suggestions are appreciated!



Inviato dal mio moto g42 utilizzando Tapatalk

You really need to remove the belt before anything else. It can change because of alternator load at anytime. If you really don?t feel like removing it, just spray it with some belt dressing when it?s making the noise.

[dmcman73]

If you have a smoke machine, use that to track down any air leaks, an air leak that is substantial in size can cause a whistle noise as well. Since you believe it was coming from the idle speed motor and you changed it, check that the cup seal under the air intake has not come out. This cup seal is hard to see and it is where the pipe (the pipe if agony) that connects to the rear port of the idle speed motor slides into under the air intake on the drivers side. With the engine off, if you remove the air filter housing and press the air meter flap all the way down, using a flash light, look towards the left side towards the rear of the meter unit, you should see the pipe from the idle speed motor sticking into the air mixture unit, that should give you an idea where it is, the seal is installed from the outside.

Other things that could cause a screeching noise would be the throw out bearing (if you have a 5 speed manual transmission), alternator bearing or a water pump that is about to fail. Do as Bitsyncmaster suggested and pull the belt off the alternator and start the car and see if the noise is gone, don't leave the engine running too long as you won't have any cooling since the water pump will be inactive. If the noise still persists, then shut the engine down and re-install the belt.

[TheStoot]

Unplug idle speed motor power, that eliminates that if sound is still present. Remove belt, eliminates alternator or water pump. U could have had this done within the 20 minutes u spent listening to the engine make noise. Do these and get back to the group