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Cooling system stuff

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by '73 K5, Apr 8, 2001.

  1. '73 K5

    '73 K5 1/2 ton status

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    2 summers ago when I had to replace my water pump I also put a new fan clutch on. One of the cheapo $21 Western Auto ones. Anyways I'm going to flush the radiator and try to get it ready for the upcoming summer...Should I replace the fan clutch now too? How long do they last? I'm just trying some preventative maintenance. TIA

    '73 K5
    Chevy good...Ford bad
     
  2. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    There's really nothing to complicated inside the fan clutch- if it still works, I would just leave it. If you're really worried, buy a spare and throw it in the truck. FYI, my 84 still has the factory clutch...............

    <font color=red>PHOTO ALBUM-</font color=red> <A target="_blank" HREF=http://albums.photopoint.com/j/AlbumList?u=1289798>http://albums.photopoint.com/j/AlbumList?u=1289798</A>.......<font color=blue>TRUCK & HIKING PICS</font color=blue>
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    My 81 still has the original too...one of the few original parts left[​IMG] Still works too.

    Rene

    [​IMG]<A target="_blank" HREF=http://jules.coloradok5.com>http://jules.coloradok5.com</A>
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    You might want to replace it if its one of the ultra cheap fluid only clutches....The gm units were both thermo and viscous fluid units...yours should have a spring visible on the front of it..

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  5. '73 K5

    '73 K5 1/2 ton status

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    I just went out and looked and the front of it is just smooth. No spring at all. Does that mean I got one of the cheaper ones?

    '73 K5
    Chevy good...Ford bad
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Yep, its a cheapy. The factory fan clutch works two ways...the fluid (viscuous) in the clutch body allows the fan to "stall" as air flowing over it reaches a point that the fan becomes a restriction, instead of pulling air, its blocking incoming air. (which is why stock clutch fans don't rob much horsepower) The spring on the front is to lock the fan when it reaches a certain temp.

    Most of my fans seem to come on about 200-205 degrees, and bring it down to about 190 before shutting off. All trucks probably got a HD fan clutch, (big) but only some of the cars got them, specificly ones with towing packages for example. Hotter the fluid gets, the less resistance it has...as the engine overheats, the fan would become less effective, instead of "locking" like a thermo fan would. I'd probably run it, but be real watchful of my temp gauge.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     

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