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replacing fan

Discussion in 'Chevy Trucks' started by rayf268, Nov 21, 2006.

  1. rayf268

    rayf268 Senior Member
    Messages: 117

    my clutch fan failed last year I installed a electric fan and its great in the summer and winter with out the plow but once last year I about over heated my truck . now I want to put a engine driven fan on for the winter and want to know what everyone would suggest I could put on the old clutch fan but it dogs the motor . If I go with a flex fan or fixed blade fan how important is it to have it spaced inside the shroud and will it pull enough air being farther away with the electric fan . I am not sure about the clearance ??:confused:
    long winded as normal
  2. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Your best bet is a stock clutch fan with a new HD clutch... the more blades on the fan the better. I didn't see what model you have. My truck originally came with a 3 blade clutch fan, upgraded it to a 7 blade HD setup.

    Fixed and flex fans don't necessarily cool any more, and they eat up horsepower and fuel mileage.

    Alternatively, get the biggest electric setup you can find and tie it into a thermostatic switch on full constant 12V so it can continue cooling after the engine is turned off.

    As for spacing a fan, if I'm not mistaken I think its supposed to be sunk into the shroud with approx 1/4" to 1/2" sticking out the back, but don't quote me on that. Maybe someone else can join in on that one.
  3. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Also pretty sure you shouldn't run both an electric and a mechanical fan... read it years ago in a hot rod mag... one blocks the flow of the other.

    Not to mention, any stock-to-moderately-modified engine should be more than adequately covered by the stock cooling system.
  4. GetMore

    GetMore Senior Member
    Messages: 179

    A clutch fan will cool more and use less power than a flex fan. The clutch allows the fan speed to remain more consistent, so it doesn't cause as much drag at high engine speeds as a fixed fan would. Because the clutch allows the fan to spin at a more or less optimum speed the fan can be designed for greater efficiency at lower engine speeds.

    Electric fans can NOT produce as much airflow as an engine-driven fan. I suppose they could if you don't mind spending a lot of money, and you have a super duty electrical system to handle it, but it's just not worth it to most people.

    If, for some reason, your clutch went bad then that is your problem. It could not be slipping enough, and therefore using more power than it is supposed to.

    If you wanted a really neat setup, you should look into an electrically operated clutch for the fan. Big trucks have them, and so does the Trailblazer. As a matter of fact, I think Jeep uses them as well. They are PWM controlled, so they never turn on 100%, but always have some slip. When not needed they freewheel.