# Buzzing Noise From Engine Bay?



## MetallicaMatt (Mar 26, 2012)

I parked in the garage tonight, started to walk away from the vehicle, car autolocked (LTZ) as normal.

But tonight I heard an electrical type buzzing noise. Thought maybe it was something in the garage, but it was coming from the engine bay of my Cruze.

Hit the unlock button on my key fob and the noise instantly stopped. Hit the lock button, buzzing started again. 

I don't think anyone would hear it if you were outside, because of wind, background noise etc, but I've never noticed this noise before, and I'm very observant when it comes to my vehicles. This sound is new.

Any ideas? I don't want to go to the dealership, where they wont be able to hear it, without at least pointing them in the right direction.


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## Jim Frye (Mar 16, 2011)

Can you open the hood before you shut it down and walk away? That might help you pinpoint where in the engine room the noise is coming from.


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## MetallicaMatt (Mar 26, 2012)

I tried but the sound was bouncing around the engine bay....I couldn't pin point it.


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## MikeW (Nov 29, 2010)

Check the following thread and see if that sounds anything like what you are hearing: http://www.cruzetalk.com/forum/9-ch.../1908-occasional-beep-sound-when-car-off.html

I don't believe there has yet been a definite answer to what that noise is.


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## MetallicaMatt (Mar 26, 2012)

This is a constant buzzing where that thread was a short duration


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## Jim Frye (Mar 16, 2011)

MetallicaMatt said:


> I tried but the sound was bouncing around the engine bay....I couldn't pin point it.


How about taking the cover off of the underhood fuse box/panel and see if there is a relay buzzing. If so, that relay may point to some circuit or function that might be having a problem.


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## rmass09 (Apr 17, 2011)

If you hear it again check and see if its from the area of the Turbo, no one seems to be 100% sure what it is but heres a large thread about it. http://www.cruzetalk.com/forum/10-e...3384-buzzing-sound-after-turning-off-car.html


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## jdubb11 (Mar 14, 2012)

search buzzing on this site or youtube and youll probably come across what you heard. this car make multiple different buzzing sounds. some are normal some are not


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## MetallicaMatt (Mar 26, 2012)

I saw the buzzing video, that's the sound! Wish I knew what it was.


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## jdubb11 (Mar 14, 2012)

MetallicaMatt said:


> I saw the buzzing video, that's the sound! Wish I knew what it was.


dont we all...i showed the dealer the video i made of mine doing it and they told me to bring it in when it does it again...like i know when that will be lmao


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## MetallicaMatt (Mar 26, 2012)

yeah, there is no point in bringing the vehicle in for this, it'll never happen when they have it, just a hassle for me....


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## Invierno (Nov 23, 2012)

Did you ever get it figured out? I don't mean to clog up another thread on this. I started my own before seeing others have the same problem it looks like lol.

Were you tuned or just stock? Going to look at that other thread now...


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## MetallicaMatt (Mar 26, 2012)

Never figured it out. Just a stock car.


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## Invierno (Nov 23, 2012)

Noted lol


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## NickD (Dec 10, 2011)

Sound travels seven times faster through metal than air, can have a source of vibration hitting a panel or a piece of sheet metal producing a loud audible sound ten feet away from the originating source. 

Have to feel for vibrations, but not easy to do if only occurs under load, unless you can run fast enough along side the vehicle. What is required is a dynamometer. Very few dealers have these, so have to do it the hard way.

Went nearly nuts with my old 78 Fleetwood, hitting the gas sounded like a huge rod knock. After a lot of testing, found that the four flywheel cover screws were a quarter turn lose. Found that noise with all four wheels blocked up and using the brakes to emulate the load. 

Matter of fact, I think I did go nuts. Oh, I dumped those 1/4"-20 screws, retapped the holes to 5/16"-24's with heavy toothed lock washers so they wouldn't come loose.


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## Invierno (Nov 23, 2012)

NickD said:


> ....unless you can run fast enough along side the vehicle.
> 
> Matter of fact, I think I did go nuts.


:xxrotflmao::xxrotflmao::xxrotflmao:


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## MetallicaMatt (Mar 26, 2012)

I agree NickD but this is definitely an electronic noise....reminds me of a electronic piezo


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## NickD (Dec 10, 2011)

MetallicaMatt said:


> I agree NickD but this is definitely an electronic noise....reminds me of a electronic piezo


Certainly has possibilities with alarm horns, speakers, and servo motors like the purge valve, power windows, TB servo motors, all those motors in the MVAC system, etc. Called hunting going back to the days when all servo motors were used, would buzz like crazy. Was a choice between absolute precision or a buzz to eliminate that hunting. Loose electrical connection can cause that, or a firmware problem.

Affected also by temperature changes, even frost can cause that so have to note the conditions when that noise is present.

If under the dash, without digging into the circuitry, blend door is suspect. Most use a feedback potentiometer. temperature control fires a reference voltage, feedback pot fires back a variable voltage to null out that reference voltage. If that pot is dirty, the drive motor will buzz like crazy. Also a binding door will cause that.

Something is amiss.


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