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  1. #1

    Default Strange noise under the hood

    Iíve noticed a strange sounds coming from under the hood recently. Iím thinking it has something to do with my A/C. Reason being that is the only time I notice the noise. The noise isnít constant but it you can hear it about twice a minute on average and it last about 2 seconds. Itís a low metal on metal kind of sound. It kind of sounds like a distant train brakes (anybody know what Iím talking about?).

    Any ideas what is maybe?

    I have a 2004 Colorado Ext Cab 3.5L.
    Jared - Ohio
    2004 Chevy Colorado Ext Cab Z71 3.5L
    2003 Jeep Liberty Limited

  2. #2


    Sounds like the compressor engaging, or trying to. Does the air work? Open the hood and leave the truck run with the air on. Just stand there and watch, if its the compressor you should know right away.
    The diference between stupidity and genius is that genius has limits.

    2007 NBS Silverado
    LT2 Z71
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    Hood Stripes
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    GM Bed Liner & Tonno
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  3. #3


    probally have to aagree with the compressor.maybe bearings are gone so when it cycles it sounds like a train grinidng to a halt

  4. #4


    The air works, it gets pretty cold. I'll run it tonight with the hood up and post my findings.

    Jared - Ohio
    2004 Chevy Colorado Ext Cab Z71 3.5L
    2003 Jeep Liberty Limited

  5. #5


    I just replaced mine and it was making the exact same noise you are describing and it ended up being the compressors clutch was starting to seize up every time i turned on the a/c.
    K1500 5.7L Chevy Suburban
    290000+ miles
    K&N CAI
    Black Bear Performance Tune
    TCI Servo and Shift Kit
    Long Tube Ceramic Pacesetter Headers
    Custom Side Swept Dual Exhaust
    Dual 2.5in electric DMH Performance Exhaust Cutouts
    BFG A/T 285s

  6. #6
    Master Mechanic CarpenterGuy's Avatar
    Join Date
    Jul 2008
    Leeds, Alabama


    I dont know a whole lot about the AC system, but if it's your compressor, it's probobly just the clutch.
    2006 Silverado Z71 - 97,000 - totaled, RIP
    2006 Silverado Z71 - 122,000 (K&N 77 Series CAI, PowerAid TBS, Magnaflow dual rear exit, 33x12.50 Mickey Thompson MTZ, Tuff Country Torsion Keys, Tuff Country Add-A-Leafs)
    1966 C10 swb stepside (Gen I 350, Turbo 400 trans, dual cyl power brakes, front discs)
    I'll keep my money, guns, and freedom. You keep the Change.

  7. #7
    Sr. Apprentice hmaster77's Avatar
    Join Date
    Jun 2009
    Kingsville/San Marcos TX


    i would check out the ac clutch
    2008 chevy silverado single cab short bed 4.3
    1960 chevy apache 10 single cab short bed 3.9
    1986 chevy 1 ton flatbed 5.7 (deceased)
    1990 suburban regency edition 5.7 (sold

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