Flex Fans Good and Bad

Heating / Cooling / AC

  1. mguner

    mguner How many is too many?

    Messages:
    5,129
    Likes Received:
    361
    Joined:
    Nov 26, 2006
    Location:
    Amarillo,TX
    Local Time:
    3:36 PM
    After seeing members and friends being seriously injured and stories of fatalities I hope to clarify which Flex Fans are the culprits of infamy and which are a good product.

    Any metal flex fan has the potential for fatigue, cracking and rivet separation. Any fiberglass flex fan which has multiple pieces riveted together is also a ticking time bomb.

    [​IMG]

    These type (below) I have never seen fail from anything other than impact.... Provided they stay below their designed RPM limits.

    [​IMG]
     
  2. diymirage

    diymirage HP@idle > hondaHP@redline

    Messages:
    21,071
    Likes Received:
    15929
    Joined:
    Oct 12, 2012
    Location:
    michigan
    Local Time:
    4:36 PM
    what do you make of the stocker on my duster ?
    (think it came from a mobile home)

    it has a metal frame, rubber blades with metal trim on the outside edge
     
  3. memike

    memike Super Moderator Staff Member FABO Gold Member

    Messages:
    49,200
    Likes Received:
    12187
    Joined:
    Jan 8, 2006
    Location:
    on the hill
    Local Time:
    3:36 PM
    I seen one of the blades in the top picture come apart and shot threw a fiber glass chebby truck hood.
     
  4. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla

    Messages:
    66,027
    Likes Received:
    39408
    Joined:
    Jun 7, 2010
    Location:
    Georgia
    Local Time:
    4:36 PM
    I wouldn't trust a flex fan of any kind. Stick with the Mopar viscous fan.
     
  5. mguner

    mguner How many is too many?

    Messages:
    5,129
    Likes Received:
    361
    Joined:
    Nov 26, 2006
    Location:
    Amarillo,TX
    Local Time:
    3:36 PM
    Anything with multiple pieces is a NO in my book for high RPM and performance applications. I have a nice factory MOPAR steel flex type unit that I refuse to put on anything as I have seen the same fans with cracks forming in the blade roots and others in pieces in the junk yard.
     
  6. jboyd2

    jboyd2 68 cuda

    Messages:
    240
    Likes Received:
    18
    Joined:
    Apr 21, 2015
    Location:
    Arkansas
    Local Time:
    3:36 PM
  7. mguner

    mguner How many is too many?

    Messages:
    5,129
    Likes Received:
    361
    Joined:
    Nov 26, 2006
    Location:
    Amarillo,TX
    Local Time:
    3:36 PM
    That is why I started this thread....

    The choice of pulleys is often overlooked when these fans fail. Many stock applications especially with A/C had large crank pulleys and small water pump pulleys thus easily exceeding the RPM rating for some aftermarket fans. All of my race car applications have run the small crank pulley which means even the engine I revved to 8500 would not have exceeded the 8000 RPM limit of the nylon Flex-a-lite had that car even been using a fan.
     
  8. fratzog lover

    fratzog lover Well-Known Member

    Messages:
    14,875
    Likes Received:
    13350
    Joined:
    Jun 7, 2013
    Location:
    Maple Shade New Jersey
    Local Time:
    4:36 PM
  9. Snake

    Snake Mopar Nut

    Messages:
    9,332
    Likes Received:
    296
    Joined:
    May 22, 2006
    Location:
    Belleville Canada
    Local Time:
    3:36 PM
    I am guilty to have the joy in owning the first one,brute ll. never again,i was stupid being 18 at the time.
     
  10. Marcohotrod

    Marcohotrod Well-Known Member

    Messages:
    2,423
    Likes Received:
    626
    Joined:
    Mar 21, 2015
    Location:
    Massachusetts
    Local Time:
    4:36 PM
    stock fans are multiple pieces
     
  11. mopowers

    mopowers Well-Known Member

    Messages:
    5,015
    Likes Received:
    2079
    Joined:
    Feb 15, 2006
    Location:
    West Sacramento, CA
    Local Time:
    1:36 PM
    So are aftermarket fixed blade fans. Anyone ever hear of one of those breaking off at high rpm?
     
  12. toolmanmike

    toolmanmike FABO MODERATOR Staff Member FABO Gold Member

    Messages:
    54,434
    Likes Received:
    40268
    Joined:
    Jan 18, 2006
    Location:
    Iowa
    Local Time:
    3:36 PM
    I was installing a blue Flex-a-lite just like the one pictured. I should have had gloves on but my wrench slipped and the hand that was holding the blade needed 6 stitches to stop the bleeding. I vote with Rusty.
     
  13. ir3333

    ir3333 Well-Known Member

    Messages:
    4,725
    Likes Received:
    1262
    Joined:
    Jun 1, 2008
    Location:
    ontario,canada
    Local Time:
    3:36 PM
    makes you wonder when the manufacturers guarantee some
    them safe to certain rpm's.
    I would have some concern about that old beat up unit you found
    at a flea market,but you would probably be o.k. with a good quality
    new one.
     
  14. nm9stheham

    nm9stheham Well-Known Member

    Messages:
    12,090
    Likes Received:
    3943
    Joined:
    Dec 20, 2013
    Location:
    Waynesboro, VA
    Local Time:
    4:36 PM
    BTW, the RPM ratings are not guarantees: they are ratings.

    I've had 3 stainless flex fans and both suffered cracked blades after a while; they crack at the side of the blade just outside of where they are clamped under the riveted holder. This is where the flexing concentrates so that is not surprising. I never had any issues with a multi-piece fiberglass bladed flex fan.

    I've raced thousands of rally stage miles on stock type, molded nylon fans with 1:1 pulley setups and revving all the time to 7500-8000 RPM, with a 3800 RPM minimum (wild cam!). Never a hint of failure. So I'm with Mguner on using a 1 piece MOLDED flex fans being OK.
     
  15. mguner

    mguner How many is too many?

    Messages:
    5,129
    Likes Received:
    361
    Joined:
    Nov 26, 2006
    Location:
    Amarillo,TX
    Local Time:
    3:36 PM
    I by no means would lean over the molded units while revving the engine and if someone has had an experience of a molded fan coming apart I would like to hear about it. I'm just saying they are a much safer and reliable unit than the Ginsu type.
     
  1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.