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No air moving with fan?!

Discussion in 'The Hokey Ass Message Board' started by creepjohnny, Sep 26, 2016.

  1. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    Hey guys. So for a long time my Pontiac runs 180-185 all day driving, but I hit traffic or a long light and temp creeps up and up and up. As high as 220. Once I move again it drops down to 185 again. So I'm getting the radiator cleaned out and notice that at an idle the mechanical fan is not moving any air! Some out the sides but just nothing. Lots of dead spots. I took a pic of how the fan was and it looked backwards to me. I take it off, flip it and it's the same amount of air flow. Hardly any, lots of dead spots and no roar of air going thru. The draw feels very low on the front of the radiator. Before I get fed up and go dual electric fans, what am I missing on this simple issue?!
    My set up;
    65 Pontiac bonneville. 389 4bbl stock. Pertronix 3 with pertronix relay. 6 or 7 steel blade fan. Fan clutch. Desert cooler high efficiency 4 row radiator, fan shroud. Hi flow water pump. Spring in lower hose.
    Fan is 1/2 in and 1/2 out of shroud. Clutch sits maybe 1- 1.5" from radiator core.
    IMG_1474937478.812037.jpg


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  2. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    well with NO clutch it WILL be a full time fan...
    ya need a different fan -n- probably a spacer.
     
  3. seb fontana
    Joined: Sep 1, 2005
    Posts: 8,444

    seb fontana
    Member
    from ct

    Does the fan spin at all with engine idling?
     
  4. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    With a spacer I will have to install the radiator after the fan. There isn't anymore room.
    How is it possible for this fan not to move any air?
    How can u tell the pitch and difference of this fan from any other?


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  5. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

  6. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

  7. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

  8. squirrel
    Joined: Sep 23, 2004
    Posts: 55,941

    squirrel
    Member

    If it's spinning slower than it ought to, it wont move much air, but it will look like it should be moving air.

    The clutches do wear out over time. If it's old, try replacing it. That setup should move a bunch of air, if it's all working properly.

    When the engine is not running, can you spin the fan easily? or does it take some effort to turn it, and it stops right away when you let go?

    also when you shut off the engine, does the fan keep spinning for a little while, or stop sort of quickly? (you need a helper to check this)
     
  9. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    It doesn't spin easily when engine is off.
    Does the fan in the pic look backwards? The leading (longer) edge wasn't on the direction the fan was going.


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  10. can you find a smaller water pump pulley, it looks really big. a smaller water pump pulley or larger lower pulley will speed the fan up.
     
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 55,941

    squirrel
    Member

    It looks like it's on the right way.

    Please excuse the spelling. I posted this with my phone.
     
  12. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    Two types of clutch fans. One is the cheaper version that is not thermostatically controlled, the other has an exposed coiled spring facing the radiator. Spring is bimetallic so it controls a valve inside.

    T-ones, when the car is stone cold, the fan roars till you get a block or two away. Then runs silent until very extreme temps of air, brings the roar back on. Takes a very high temp to kick it back on.
     
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  13. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    Pulleys are all original. Interesting point.
    Don't think this one had the spring facing the radiator that u mentioned. Maybe it's a cheaper one that is finally going out.
    Just seems strange that the would be no air moving thru it at all. Didn't seem like it wasn't spinning slow or anything. If that's the case I guess this is my first bad fan clutch. Didn't think these things "wore" out.


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  14. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    If you get a new one, see if they can get the correct thermo one for your car and your blade.

    They work well, and you have piece of mind, knowing it will "kick in" when it gets too hot, before boiling.

    It's nice not listening to a high pitch fan if it's not needed.

    The old add-on A/C conversions in the 60s-70s, had a solid non clutch with very aggressive pitch and was awful to hear all the time.
     
  15. robtlor
    Joined: Dec 7, 2010
    Posts: 118

    robtlor
    Member
    from Lincoln NE

    Fan looks to be on right, clutch has failed.
     
  16. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    Alright guys, thank u for the info. I'll look into a new clutch. Was wondering why there wasn't enough draw. And this explains why my buddy with a 65 bonneville with no shroud and a 4 blade fan could sit in traffic and I couldn't. Ugh, cars


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  17. If the fan is spinning clockwise its hooked up right, pulling air.
     
  18. rtp
    Joined: Aug 14, 2007
    Posts: 221

    rtp
    Member

    This may sound iffy ... let engine warm up take a piece of heater hose 2ft long double over hold ends in hand slowly and i mean slowly push it in to fan ( from the angle that you took the picture of the fan) the back side of the blades !
    The fan wont catch it . If the clutch is weak the fan will slow down . DO THIS ONLY AT IDLE!!!! If clutch is ok
    it wont slow down. Now dont just stick the hose in fast and deep or the fan may get you (not good) or you my need a new radiator and fan water pump etc...
    Saw this test done many times . always worked . BUT do it SLOW and CAREFUL!!!!!!!!!!!!!!!!
     
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  19. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

  20. I was having the same problem with my '39 convertible,I had the same size water pump pulley as the crank pulley,I installed a smaller W/P pulley and the water temperature dropped dramatically. HRP
     
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  21. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 2,314

    19Eddy30
    Member
    from VA

    X2
    Pully size do matter ,
    Also try what RTP suggested ,
    BUT BE CARFUL, especially if the clutch is good !!
     
  22. chargin03
    Joined: Jan 8, 2013
    Posts: 516

    chargin03
    Member

    You can make it work by putting sheet metal screws in the front of it. That Locks it up and makes a good test.
     
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  23. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

  24. Thanks for reminding me!
    This trick really helped my OT Jeepster so it should help my 50
    [​IMG]

    The top one is 5" off an 82 s-10 with the goofy little v6, and is sitting on top of my original 6"

    The original s10 one is actually 4 groove. Drill out 2 spot welds and you get 2 try's to get one to fit. The one shown is the deeper 1/2. The front shallow one is on my car now

    Good luck with yours




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  25. [​IMG]

    And here is the front 1/2 of the s-10 pulley on my mid 70 Pontiac 350


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  26. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,801

    jimmy six
    ALLIANCE MEMBER

    When cold take the rad cap off and start the engine. Let it idle until it his hot and you are sure the thermostat has opened. Look in the rad see if there is any movement of water if none raise the idle slightly, I mean 100rpm or less, if you see water movement a smaller pulley will solve the problem. YBlock guys do it all the time. This 15% methanol gas doesn't help either..good luck.
     
  27. creepjohnny
    Joined: Dec 1, 2007
    Posts: 905

    creepjohnny
    Member

    Poked my head under the hood after work. The water pump pulley measures 8" !! I'm sure a 6" will help that out. Anyone know a good place to find a 5-6" pulley, 2 groove that's about 1 3/4" overall depth?



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  28. Richard Head
    Joined: Feb 19, 2005
    Posts: 535

    Richard Head
    Member

    NAPA has 3 grades of fan clutches for 60's-70's GM engines. Standard, heavy duty and severe duty. I put a severe duty on my 67 GTO w/AC, and never looked back. The only problem is that it is noisy (like a big truck) before the clutch warms up. A heavy duty clutch probably would have been quieter at start up.
     
  29. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,534

    50dodge4x4
    Member

    Are you sure the radiator fins are not just plugged up with dust, dirt and other stuff and the air can't flow through it? Its seems pretty strange the current system has worked for all these years, and now somehow the pulleys are the wrong size? Either the clutch has gone bad, or the radiator fins are plugged up and the air can't pass through, or a combination of both. Wash the rad fins out with a pressure washer from under the hood towards the front bumper. If that doesn't do the job, change the fan clutch. Gene
     
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  30. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,214

    sunbeam
    Member

    He said it cools ok on the road kind of rules out the radiator.
     

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