Frightening squealing sound from the engine

[JohnZ]

Hi there and happy Christmas!

My car lately has been producing a frightening noise from the left side of the engine... judging by the ear it could have been the Idle Speed Motor, possibly seized, so I replaced it with the DeloreanGo one. The noise appears at idle and at certain rpms, it's a loud squeaking noise, just like a pig being slaughtered!

Unfortunately replacing the Idle speed motor didn't solve the problem! A 40 minutes ride and the noise came back at full force! It just happens when the car is hot, I hope you can shed some light on this!

Here's a quick video I made today... enjoy!

https://youtu.be/ncqYLBKk7Fg

[Bitsyncmaster]

Pull each belt off and test if the noise stops.

[JohnZ]

Thanks Bitsyncmaster! I'll definitely try that! besides, I just have one belt, because the A/C one has been removed due to a bad bearing

Here's another reference: the sound is scary, but something tells me that it's just a little something that is wearing out, and it should be an easy fix...as long as we pinpoint the problem!

https://youtu.be/hdEaKhiq8pM?si=2FBdjUdJLovCEiZB

[David T]

Sounds can be "sneaky", seems like it comes from one place but is really coming from somewhere else. Since you only have one belt on it is probably either the water pump or the alternator.

[JohnZ]

Thanks David for your precious feedback! I replaced the alternator just a few years ago, but the water pump is the original one...

Do you think that I should replace it? Is this noise a "common" thing?

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[Bitsyncmaster]

Thanks David for your precious feedback! I replaced the alternator just a few years ago, but the water pump is the original one...

Do you think that I should replace it? Is this noise a "common" thing?

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If you remove the belt and noise is still there then it's not the alternator or water pump.

[outatym2001]

Here is my suggestion. Take a small diameter rubber hose about one meter long and put one end of the hose in your ear and the other end of the hose you can search for the source of the horrible noise.
I located an air leak from a paper gasket on my air inlet manifold. I had to loosen the bolts and retighten the bolts for the noise to go away.
The paper gasket is in the DeLorean Parts Manual on page 1/4/1. Engine Air Induction System.
Item number 52 INLET MANIFOLD GSKT.
Please let us know if you find the source of the horrible noise.

[JohnZ]

Thanks a lot for the inputs guys, and Merry Christmas to you all!

I'll definitely run some tests and I'll keep you updated!

The shrieking DeLorean is soon to be silenced!

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[JohnZ]

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!



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[AugustneverEnds]

I wonder if there is something stuck in your idle speed motor. It might be worth taking it off and having a look.

Or has something found its way into the mixture control unit? Maybe take the air filter box off and press the air metering plate down, shine a flashlight in there and see what there is to see.