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Loud fan?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Magnus88, Jul 13, 2003.

  1. Magnus88

    Magnus88 Registered Member

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    I dont know if it is just me, but i think my fan is really loud. When i rev my engine i mostly just hear the fan going and not the sound from the exhaust. Maby its just the restrictive stock exhaust (witch i havent gotten around do fixing yet) that is the problem, but if you stand in front of the truck when ideling you barely hear anything byt the fan, and the A/C compressor clutch "klicking" every few seconds. I was thinking maby one of the fan blades is warped or something but it looks ok... Well i just thought id hear what you guys have to say about it.
     
  2. Confedneck

    Confedneck 3/4 ton status

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    could be the fan clutch...??
     
  3. 88Silverado

    88Silverado 1/2 ton status

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    My 88 with the tow package has a Really loud fan.
    At idle, the fan is real quiet. When you give it the gas, its loud, especially if you have been driving it for a few and have stopped at a signal or something.

    The thermal clutches on are pretty stiff. The fan pulls quite a bit of air when the fan is engaged. When I first got mine, I thought the clutch was stuck but its normal.
    Usually you can hear the fan starting to disengage several seconds after you hit the gas.

    The airconditioning clutch engaging and disengaging every couple seconds usually means its getting low on freon. Mine was cycling every 3 seconds so took it and had it charged.

    Im still thinking about changing my fan to the dual f*rd winstar fans and trying that to quiet things down.

    When its cool, see if you can spin the fan by hand. It should rotate with a fair amount of resistance. If you cant move it, need to replace the clutch.
    Basically what you described sounds normal (except the air). /forums/images/graemlins/tongue.gif
     
  4. Magnus88

    Magnus88 Registered Member

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    When cool i can spin the fan by hand with, as you sad, a fair amount of resistance. But i dont belive i have ever noticed that it disengages. Should it completely stop moving or what? Is the rolled up piece of metal in the center of the fan the thermal clutch?
    Before i did the bodylift you could hear a sort of helicopter-type noice like floff-floff-floff-floff... /forums/images/graemlins/grin.gif but since i modyfied the schroud when lifting that went away.
    As for the A/C i know it is out of freon but didnt know it was the reason the compessor was going on and off all the time. The trouble is i dont belive i can get it filled with the freon its supposed to have because of enviromental reasons. Ive been told that it neads som type of conversion to be able to work with the newer type of freon. And ill bet thats not done for free... /forums/images/graemlins/frown.gif
     
  5. the professor

    the professor 1/2 ton status

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    YOu have A/C... the A/C always needs air flow over the condenser, to keep the freon from overheating/overpressure ...thats why when you have electric fans, they ALWAYS come on with the compressor, no matter what the engine temp
    --
    There are several different fan clutches, std thermal, HD, and A/C..

    The standard thermal, spin mostly loose when turned cold by hand with some drag, will spin-up after you first start it, then just about freewheel and slow down, then they start to "spin-up" again at a pre-determined temp (they always slip) to the rated rpm

    The HD units, start at an earlier temp, and turn the fan at a higher rpm

    You can usualy hear either one of these units.. You start up, hear the fan, then it goes away, then comes back when the engine gets hot...

    The A/C unit works just like the first to, but NEVER completely freewheels... Just turns the fan slower when it is cold, and usualy is set to a higher rpm like the HD units...

    When the units go bad, they either get tight, and stay at high rpm, or freewheel all the time... not counting wearing out the bearings and such...

    Got to watch those units that are turning realy hi rpm, they can crack and throw blades... /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  6. swampblazer

    swampblazer Registered Member

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    the freon you are talking about that comes factory in your K-5 is R-12. and is illegal now a days b/c of fewderal government bullsh*t. their is a kit called a retrofit kit. whichs converts the R-12 to R-134a. which is ok i guess oh well just tellin ya!
    peace
    luke
     
  7. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    stock fan? my flexalite was loud as all hell, but the 3" exhaust balanced it out.
    Grant
     
  8. 88Silverado

    88Silverado 1/2 ton status

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    If its cool outside you will hear the fan loud when starting to accellerate, after a few seconds you should notice the noise going down. Thats when the clutch is loosening up. The spring coil is the thermal sensor.
    The A/C compressors hsve a low pressure switch which will keep kicking out the compressor so it doesnet get damaged.
    The usual conversion for the freon is from R-12 to R-134. It is a minor modification in most cases.
     
  9. tecton

    tecton 1/2 ton status

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    ive noticed this too

    side exit exhaust fixed it /forums/images/graemlins/smile.gif
     

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