# Engine noise hadn't heard before...



## sciphi (Aug 26, 2011)

Couldn't hear it. It sounded like intake noise to me. 

When does this whooshing noise happen? It's normal to hear the turbo a little bit at 1500-2100 RPM before it gets drowned out by other engine noise. 

Also, air can act as a fluid, the turbo piping is a conduit, and the turbo is an air pump.


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## hubbardgd (Jun 15, 2011)

I notice it only at idle. I can hear it from inside the care as well as outside. I have to have everything off (radio, heat fan, ect) to hear it from inside the car. Again, it's a cyclical sound that occurs about every second (whoosh...whoosh...whoosh...whoosh...whoosh...whoosh...whoosh...whoosh). Again, in the video if you listen carefully, you can pick up on the pattern under the normal engine noise (it is hard to hear, though).


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## limited360 (May 6, 2011)

when the car is cold or up to temp?


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## hubbardgd (Jun 15, 2011)

Up to temp...


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## limited360 (May 6, 2011)

hmmm I get the whoosh whoosh when cold as I have idle surge issues since I bought the car..


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## mzodarg (Sep 3, 2011)

Are you sure the noise is not related to the intercooler? I hear mine more when I am in the M mode.

Tre'


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## Dale_K (Jul 16, 2011)

My non turbo LS made a noise like this and it turned out to be the A/C compressor. It only happened when the A/C button was off. As soon as you turned on the A/C the noise would stop. They had to replace my compressor twice before they fixed it. The service writer said the same thing happened to another customer (two replacements needed). If you take a big screwdriver and use it like a stethoscope you'll probably hear the sound very clearly when you touch any metallic fitting in the A/C system.

On the LS there is no clutch on the compressor pulley so the shaft spins all the time. I think the ECO has a clutch but I don't know about the other models.


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## thevoid (Aug 1, 2011)

Dale_K said:


> On the LS there is no clutch on the compressor pulley so the shaft spins all the time. I think the ECO has a clutch but I don't know about the other models.


I find this hard to beleive. What is your source for this information?


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## sedanman (Dec 10, 2010)

sciphi said:


> Also, air can act as a fluid, the turbo piping is a conduit, and the turbo is an air pump.


Air doesn't just act like a fluid, it IS a fluid! lol


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## hubbardgd (Jun 15, 2011)

Sorry for the delay. I finally took my vehicle into the dealer to have them check it and as Dale_K mentioned, it turned out to be the air compressor. They replaced it and it was of course under warranty, but I barely have 12,000 miles on the car. I guess it's a good thing we have the 5-year/100,000 mile warranty on the drivetrain to hopefully cover the air compressor if I have to replace it a second time


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## tomthebomb (Feb 16, 2012)

And here we were all along being taught in classrooms all across America that air is a gas.


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## Dale_K (Jul 16, 2011)

thevoid said:


> I find this hard to beleive. What is your source for this information?


You can see the pulley assembly very clearly and there is no clutch. GM has a variable displacement compressor that can be regulated internally even though the shaft is spinning at all times. I don't have an ECO but I've read they have a clutch to eliminate the slight parasitic drag.


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## thevoid (Aug 1, 2011)

Does anyone have a picture of the 1.8 compressor? I have never seen an automotive compressor without a clutch, including my Cruze 1.4T


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