1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Cooling fans

Discussion in 'Gen 3 Prius Main Forum' started by Ed480, Oct 10, 2023.

  1. Ed480

    Ed480 New Member

    Joined:
    Jul 10, 2023
    13
    1
    0
    Location:
    Mesa
    Vehicle:
    2010 Prius
    Model:
    Three
    I was wondering does the 2010 Prius cooling fans have 2 speeds? I am still having overheating issues after replacing the water pump and thermostat. I used oem parts. The fans seem like they are not spinning fast enough. I was driving with the obd reader and looking at the ECT temp and my over heat light comes on at 213f.
     
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    8,924
    1,553
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    I Believe those fans are variable speed or two speed or more than low so you need to find out why that is when your air conditioning is on the fans should be on max so you should see what your car when it says it's at 2:13 and you pull over if you were to turn on the air conditioning does the fans get real loud then they weren't on high when the car was on 213. You need to get that sorted so maybe the temp sensors in the radiator or the head or the block or whatever aren't sending correct information on a 2010 Gen 3 those fans could be $300,000 mi old it might be time.
     
  3. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    7,918
    4,680
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    The fans are two speed and there are two coolant sensors. 213f is not enough to trip a warning so it must be the second sensor.

    If the car is moving you should not need the fans this time of year. However ac on will turn on the fans regardless of coolant temps.

    You need a bi-directional scanner to test both speeds. An obd2 scanner like “Car Scanner” can read both coolant temps. While unlikely a sensor could be bad.

    You should also verify coolant flow into the reservoir when the engine is heated up over 185f or so. Cheap water pumps, bad wiring, relays or fuses could be a problem.

    Two sensors to combo meter.jpeg

    Prius gen3 coolant sensors.jpeg

    Prius gen3 Cooling Fans.jpeg

    Prius coolant relays.jpeg
     
    Brian1954 likes this.