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Electric Fans?// Good/Bad

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by reddog64, Mar 17, 2001.

  1. reddog64

    reddog64 1/2 ton status

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    I want to get rid of my stock fan and put in a dual electric fan setup... Has anyone done this? Is there any problem running a electric fan in place of the stock clutch-fan??? Will teh mmotor run just as cool as with the electric ones??? Should they push or pull???

    Um... yes officer I know it's too big...
     
  2. Chaz88K5

    Chaz88K5 1/2 ton status

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    i would say get a flex fan...my friend has a electric on his 70 bronco and it just exploded last night...he had just finished puttin it on and started the motor..well a few min alter the fan kicked onand every blade on it riped off...it just nicked a peice of plastic and blew it appart...i have also heard storys of someone goin into a water crossing and forgetting to turn the fan off while goin through it and it rips all the blade off from that too....so i think a flex fan you would be alot better off

    Chaz

    "Hondas look good under a k5's tires"
     
  3. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    There are no clear answers here. Everyone has a different opinion and it also depends on what you do. I'll try to summarize to the best of my understanding. Be aware that most designs depend on the truck's movement to force air through the radiator.

    Typical Factory: Pretty good all around setup. Driven by engine through a viscous clutch that is adjusted tighter/looser based on temp using a bi-metallic strip. Engine compartment gets hotter, fan tightens up. Cools down, loosens up so it does not rob HP. For instance, driving down the highway, the fan pretty much should freewheel because you get plenty of airflow due to pushing a mass of air in front of your brick, er, I mean truck [​IMG]. This provides a good mix of reliability and efficiency as long as the clutch is in good order. Down side is it takes some (very few) HP to spin it when the temp goes up (for example, 4 wheeling) and it can go into the radiator when twisted if clearances are tight or if something breaks. It also does not work well if the engine is idling for long periods.

    Flex: Similar to the clutch, driven by the engine. However, it never free wheels. It's only adjustment is based on RPM. Higher RPM, the blades "flex" and flatten out pulling less air. Power draw is basically constant and it is always pulling air regardless of temp requirements. Down sides are noise, does not work well at idle, constant power consumption and, it can be dangerous while working on the engine. The clutch type can certainly hurt you but generally not it is not major since the clutch will slip before doing too much damage (depending on rpm and temp). The flex fan can cut off fingers easily since fingers are not usually strong enough to stop a V8. It also does not work well idling. A very simple and dependable setup but I personally don't like it.

    Electric Fans. Uses no engine power and are usually controlled using a temperature thermostat that goes in the coolant system. Very good demand based control but more parts to go bad. Main advantage is that it works well even when idling around, no danger to radiator and very little to fingers, no HP consumption. Can also be mounted out of the way when engine/radiator clearance is tight.

    To push or to pull. Pulling is generally regarded to be better since it allows better air flow when moving down the highway. Pushing is good when there is no room to pull and can be combined with a clutch or flex to handle idling for long periods but it can reduce airflow from movement.

    That's all I can think of.

    Bad Dog

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

    Cavalry 1/2 ton status

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    I would not elimainte a mechanical fan....I have had electrical system meltdowns in the middle of nowhere....that leaves you with no cooling system. I am a firm believer in KISS (keep it simple stupid!)

    Luke
    84 K5
    [​IMG]
     
  5. belly

    belly Registered Member

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    Yeah, the more basic the system the better. I've run a combination of both over the years in race cars and 4x4's and the only setup which has never given me grief is the clutched fan. Even if the clutch is broken (siezed or loose) you can still cool your engine when wheeling or towing or just putting around town. Nuthin sucks like the stock fan.
     
  6. Thumper

    Thumper 1/2 ton status

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    Well, I run dual 13" electric fans and have for nearly 2 yrs now. I have never had trouble with them cooling the engine, and as far as Im concerned, the ability to turn them off in water is worth several rads. But as was already said, its totally a matter of preference. I like them.

    Mike


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Lets Go Wheelin! </font color=red>
     
  7. k5king

    k5king 1/2 ton status

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    i used to have two elec. fan's hooked up when i mud raced...we alway's needed to get the eng. temp. up just before the run so i would turn them off to get it nice and hot,,and when i reached temp. i just flicked a switch and in a matter of second's that thing was frosty cold,,this was without using a thermostat too..i ran that thing in some pretty nasty mud for a year and never had any problem's,,still got the rad. and fan's too,,gonna put it on my rig next,,,but,,i am going to carry a flex fan with me just in case of the short circuit,,,alway's go prepared[​IMG]
    oh and by the way,,i used two fan's from a subaru,,they are very small and compact,,i think they are only 10" fan's,,,but they sure do pull some air!!


    ANYBODY LOSE THEIR JEEP????????[​IMG]
    I JUST FOUND ONE UNDER MY BLAZER!!!![​IMG]
    [​IMG][​IMG]<P ID="edit"><FONT SIZE=-1>Edited by k5king on 03/17/01 06:55 PM (server time).</FONT></P>
     

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