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fan clutch bad??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by drifter, Sep 27, 2000.

  1. drifter

    drifter Registered Member

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    I am still having engine overheating problems, I have replaced the radiator, water pump, thermostat, the fan shroud is sealed up good. the timing is set right. The only thing left i know of is the fan clutch, but how do you tell if it could be bad? When the engine warms up I can get a few rpms up and the fan keeps turning awhile after i shut the engine off. This part sounds crazy but, when i am on the highway is when it overheats but when i slow down it starts cooling off. hhmmmm. Thanks for the help!!

    Life is grand in K-5 land![​IMG]
     
  2. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    If your fan clutch is bad, you'll know it. Take your truck out on the highway and get her up to about 60 mph in Drive- if the clutch is stuck on, your engine will sound like it is over-reving, almost like you left it in second gear by accident.

    Another issue overlooked in overheating scenarios is tranny problems. If your tranny isn't working properly, this can cause the motor to run hotter.......
     
  3. fr8train

    fr8train 1/2 ton status

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    could this happen at low speed say 20-35mph?
     
  4. Sound like another problem to me.The fan would only affect cooling at idle or realy slow speeds.Your thermostat could be sticking.You could also have the block flushed and see if that helps.If that dont work you could have a blown head gasket or a cracked head.If the flushing don't work have a compresion test done.
    Hope this helps,good luck.


    IF IT AINT BIG IT AINT BAD!!!!!!
     
  5. '73 K5

    '73 K5 1/2 ton status

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    Look at the little spring thing in the middle. I heard that if oil is leaking out around that part then its time to get another one.

    '73 K5
    Chevy good...Ford bad
     
  6. Thunder

    Thunder 3/4 ton status

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    Did you maby install the thermostat upside down? That can cause overheating at freeway speeds
     
  7. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    If you're referring to the reving sound, fr8train, you may hear the same thing at the top of the rpm band in 1st before your tranny switches to 2nd, and 2nd to 3rd, and then again when you reach high rpms in third. The sound is an unmistakeable roar- like a mini jetplane under your hood.

    So if you gun it off the line, and you reach 25 mph before you drop to second, you may hear the "roar" if your fan clutch is stuck on..........it should disappear once your tranny switches gear.
     
  8. DMK

    DMK 1/2 ton status

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    Did you try to hook up another gage to see if yours is right? If that is not it, I would go along with bigbad82k5 and try flushing the block.
     

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