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Opinion on Electric Fans

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by GRINCH, May 13, 2001.

  1. GRINCH

    GRINCH 1/2 ton status

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    Pro's and Cons please.

    The Few, The Proud, The K5 Blazer
     
  2. 90blzr

    90blzr 1/2 ton status

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    I just put on 2 of the perma cools fans with the painless wiring relay and sending unit kits. They are 16" and flow up to 2950cfm each. They seem to work great. They are pullers. I didnt have the shroud before so it would run a little warm at times anyways and now it doesnt seem to heat up at all with the exception of towing up a grade, it got pretty warm. I guess I could still put the stock fan on for towing to help out. Also all of the crap in front of the radiator doesnt help either (tranny cooler, oil cooler, a/c condensor, etc.) I have the normal 3core radiator too. I thinks I saw a post a while backe about using a radiator for a 1 ton and you just have to make the top hold down, so i might do that, I am sure I wouldnt have any problems then. There is a noticeable power increase without the drag of the clutch fan, not alot, but noticeable. Havent checked mileage difference yet. Let me know if you have any questions.
     
  3. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    The stock setup on your year is the most reliable and efficient (for pulling air, cooling), robs powere tho.
    Equally important is the shroud.
    What are you trying to accomplish?
    Since your Geo region gets hot, I would stay stock.
     
  4. GRINCH

    GRINCH 1/2 ton status

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    I'm going through the truck and next week am installing a new motor( See post on finally deciding on new motor) and just thought since I was at it I would do the fan. I'm only in Ga. for a few more months and will be looking towards Montana or Northern Idaho.
    Just looking to get more torque and HP.

    thanks.....

    The Few, The Proud, The K5 Blazer
     
  5. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    That would be the good reasoning then. Make sure that the system is redundant - at least 2 fans that can operate independantly if necessary. Georgia to Montana - culture shock!
     
  6. Pure Insanity

    Pure Insanity 1/2 ton status

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    im running a single fan off of a thunerbird.its a 2 speed and rite now ive got it on low.seems to work fine.ill have to wait to see what happens this summer.i live in fla.gets kinda toasty here.if i have a prob ill have to drop back and punt.

    PURE INSANITY
    86 blazer see it at:<A target="_blank" HREF=http://www.zing.com/album/pictures.html?id=4292792569>http://www.zing.com/album/pictures.html?id=4292792569</A>
     
  7. BIGRIG

    BIGRIG 1/2 ton status

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    I've got one electric fan right now (16"caught it on sale for 25$) I have it as a puller with a new from advance auto radiator(4 core HUGE!) same exact hight
    and width all I had to do was cut and weld my hold-downs, but I think If you go to Chevy they have ones to fit. Either way I'm runnin a 383 with a 160' thermostat and I cant get it to break 170'.
    I ran it off of a fan switch out of a chrysler and screwed it into the water pump, ran a relay and about 3 wires, and now it tturns it self on and off when needed. I'm going to add a second fan(12") as a back-up as a pusher and a switch that is set for the 220 range just as a back-up. To put the fan on all I did was went to the hardware store and bought a 1" strip of metal w/pre drilled holes in it and used that as monting straps. then drilled holes in top and bottom of radiator, threaded the holes and put the fan on.
    LOVE it!

    If you want part#'s or questions just email me.

    Chris Clay
    KINGBIGRIG@PRODIGY.NET


    MY DRINKING TEAM HAS A FOUR WHEELING PROBLEM!
     
  8. xtreme_wlr

    xtreme_wlr 1/2 ton status

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    One thing that will help cooling a good deal is swapping in a big-block radiator. Get the radiator, shroud (i think its the same for a small block and the radiator supprt for a bigblock of similar year and you are set. Waxer, a regular here, has done this on his small block K5 and my roommate has too. Works great and all the parts are readily available.

    '78 Chevy 1 ton Stepside RockCrawler
    468 BB, SM465, NP205
    D60 front, GM 14Bolt rear w/ Detroit
    <A target="_blank" HREF=http://65.11.18.114>http://65.11.18.114</A>
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Either an electric fan or a clutch fan will "rob" power. Clutch fans only take about 5hp though, and cool exceedingly well. Cons? Hmm, that they leak fluid when they fail? Puts a little more load on the water pump bearings?

    Pros: No extra wiring. Electric fans should (IMO) be wired to turn on/off when motor reaches X temperature, a lot of people just slap them on their with no thought to a temp control. Stock fans ARE temp controlled, and "stall" at high RPM's, to increase airflow through the radiator. A fan that is on all the time makes the cooling system less efficient while cruising.

    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  10. Burt4x4

    Burt4x4 3/4 ton status

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    Howdy, I use the Flex-A-Lite BlackMagic M150 that Summit Racing sells. I live in the central valley of California and it is common to have 100 deg summers and the M150 is able to keep my mildly built 350 185-200 deg. I am very hapopy with this fans cooling ability.

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     
  11. GRINCH

    GRINCH 1/2 ton status

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    Thanks all. I will probably stay with the stock fan or install a flex fan.

    Burt4x4, Any mods to install the flex and why is it better than the stock?

    The Few, The Proud, The K5 Blazer
     
  12. Hathaway

    Hathaway 1/2 ton status

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    Hey Montana, great place to live. I live here so it must be right? [​IMG] Where abouts over here you looking? Sorry I know its off topic but just had to ask.

    Dan, '86 K5, 5.0L v8, NP208, TH700R4, open 10bolts front and rear, 3.43gearing, K&N filter, 31x10.50R15 Trailhandlers
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    A plain flex fan is a BAD idea. Not only do the metal ones come apart (see the GM recall on teh old stock ones) but they cannot "stall" like stock fans, thus robbing power the faster you go, and hampering cooling because they act to block air through the radiator at cruising speeds. They say they "flatten" out, nonetheless, they are still there, and spinning constantly, whether the engine needs it or not.

    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  14. Toad

    Toad 1/2 ton status

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    I think you can buy a thermal clutch for your stock fan that engages only when necesarry. What part of Idaho might you be going to? I used to live by Idaho Falls and you definately do not want your fan runnig when it is 10 degrees out side. Your heater will barely keep you warm. Try and find a thermal fan if they are still available. Maybe Summit caries them. I can't remember.
     
  15. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Stock fan with the bi-metalic coil is THE way to go. It has a viscous coupling that adjusts for engine temp and rpm to give you what you need without unnecessary overhead. Just don't get the cheapy clutch without the coil on the front. I wouldn't consider a flex fan at all for the reasons mentioned PLUS it acts like a saw blade if anything (including your arm) gets into it. The only time I would consider an electric fan is when you have space issues on an engine swap (like Jeeps/Samis).

    Bad Dog

    85 K30 CUCV, 350 TBI, TH400, NP205, D60/C14, 4.56 Locked
    Soon: 4" lift, 40" tires, massive cutting, shorter wb and rear overhang.
     

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