How do I know if my fan clutch is bad?

Discussion in 'General Chevy & GM Tech Questions' started by OldPitPony, Sep 25, 2009.

  1. OldPitPony

    OldPitPony New Member

    Hi All
    I have a 2001 S10 4.3L V6 Automatic with A/C. I swapped out the DexCool for Prestone yellow about 3 weeks ago, my temp guage came up to just under 100 Celcius, about 195 Farenheit and the upper rad hose got real hot, I figured all was good. Now the weather is colder and the temp guage doesn't rise above the one quarter notch mark, the upper rad hose never gets hot, there is only minimal heat in the cabin heater.

    I notice the fan is spinning now at all times, from as soon as the engine is started, even if stone cold. With the engine off and cold, I can spin the fan with only minimal resistance, with engine off and now warmed up as much as it will warm, the fan clutch still spins with only minimal resistance.

    I understand there is also a temperature sensor on the left head area, this can apparently run my engine in a "rich" mode.

    So how do I tell if my fan clutch is my problem or the temp sensor is causing the engine to run in a "cold mode"?

  2. gunsap

    gunsap New Member

    The fan clutch will some times show signs of leaking also will wobble or move around. I would recomend going back to dex cool as well. hope this helps
  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    It sounds like your thermostat is stuck open. If it's open all the time the engine will not get hot in cold weather and your heater will blow warm but not hot air.
    As for the fan it should have resistance when you turn it when it's cold. If you can spin it and it turns 1 revolution by itself it's a sure sign the clutch has lost all it's fluid.
    As for the sensor, it tells the computer when to go into closed loop. If the thermostat is stuck open the PCM will keep your engine in open loop where it runs rich and wastes fuel. All this can be seen by watching the data on a scan tool by the way.

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