Fan Troubles 2001 Honda Accord 1.8ltr F18b2 Engine

Discussion in '6th Generation (1997-2002)' started by Desperate Dan, Tuesday 10th Jul, 2018.

  1. Desperate Dan New Member Getting Started

    United Kingdom Dan Witney
    Hi All

    This is my first post here and unfortunately I'm asking for help. Bear with me as i describe my troubles as, though im mechanically minded, my knowledge of my own Honda Accord is woefully little.

    So, the model is a 2001 Honda Accord 1.8ltr F18b2 Engine

    I started my troubles by noticing that at random points in time my temp gauge would spike into the max (not gradually just instant)

    So I've started with replacing the thermostat - this seems to be working better (old one was very stiff i could hardly move it with my fingers, new one, though gave resistance could be moved with force)

    Top radiator pipe runs hot to the touch after around 10 minutes of idling (can only hold hand on it for a couple of seconds) and though still hot, the bottom pipe is much cooler. I'm thinking i have good flow, no hard pipes in the line.

    I've checked fuses (found two listed for the cooling fans, 20Amp under the hood and 7.5amp by the drivers side fuses) both are fine.
    Have swapped relays from ones that i know are definitely working to the cooling fan relay slot and still nothing.
    Have changed the temperature sensor by the thermostat, still nothing.

    Have taken connector off the temperature sensor and bridged with wire and both fans kick in instantly.

    I've tried to bleed any air out of the system as much as i can, opening the radiator cap, starting the engine, squeezing the top rad pipe then topping up with coolant, rinse and repeat till no more air would come out.

    When I put the AC button on in the cab neither fan comes on.

    The only thing i haven't checked is resistance on the new sensor (will be trying that tonight as it may be a faulty sensor) and checking that im getting voltage to the fan connector when the temp sensor is in place and wired in.

    Any other ideas would be great!
  2. Harvey Club Veteran ★ ★ ★ ★ ★


    I hope this helps I diagnosing the problem that your having mate. As promised I checked the ESM, this should be able to give you test values and where to check wiring.
    andy83 likes this.
  3. Desperate Dan New Member Getting Started

    United Kingdom Dan Witney
    Is this really saying that the coolant directly inside the engine block should be 103-109 degrees C? If so then my accord is probably not running hot enough for the fans to kick in!

    Ran it earlier today and was reading the engine temp sensor with an OBD box linked to my phone and after 10 minutes of Tick over she only got up to 95 degrees!

    Surely if I’m bridging the fan switch with a wire and the fans come on then all the wiring, relays and fuses should be intact?
    - - - Updated - - -
    Also as a side note, found that if I tap my dashboard just above the temp gauge it maxes out! If I tap the glass it goes back to normal (about 2/5ths)
  4. Harvey Club Veteran ★ ★ ★ ★ ★

    This was a video I took of mine while I was diagnosing an ABS. If I remember right my temp guage always sat a little under half way. Though I think in this video I had been running the car but not for long.
    Desperate Dan and andy83 like this.