I have a 2008 Honda Accord EX 3.5L V6, with about 152k mileage.

Very recently, after driving for about 15-20 minutes of a normal commute, I shut my car off, there is a noise (radiator fan) noise coming from the hood which lasts for maybe 10-15 minutes then stops. This occurs when the temp gauge goes slightly over the middle operating temp, and seems to be frequent.

Thermostat has been replaced recently, and so they drained and refilled with a gallon of Honda antifreeze. The coolant reservoir appears full, but when engine is cold, the radiator fluid is NOT filled to the top, so I kept filling the radiator up but it keeps going down instead of being filled up to the top (reservoir is already at max). Isn’t the radiator fluid sealed by the cap supposed to be filled to the top when it’s cold? Also, since the shop refilled with just 1 gallon and my car takes nearly 2 gallon, I assume I still need more antifreeze but the reservoir appears full, slightly confused with the reservoir and amount of radiator fluid sealed by the cap

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Jan 26 at 12:02
  • I’m a little curious too, if I’m checking the coolant level in the morning when it’s cold, the reservoir appear full, but is the radiator fluid sealed by the cap Also supposed to be filled to the top when it’s cold?
    – Emad
    Commented Apr 22 at 4:32
  • Your Accord has an overflow bottle (stock it should have a yellow plastic cap with a hose going to the radiator). This is where you should be checking you coolant at. There are two marks on the side. One is for checking when cold. The other is for checking when hat. Realistically, at anytime, your fluid level should be right in between the two. On a different note, if the below answer answered your original question, we ask that you select the checkmark to indicate it has been answered for you. Commented Apr 22 at 9:40

1 Answer 1


It is not uncommon for the fans to stay on after the vehicle is shut off. This is how it is designed to work if the engine coolant is too hot.

If it is new behavior that the fans are staying on yet nothing has changed and the dash gauge isn't showing a temperature issue, it may be that the engine coolant temperature sensor might be going bad. The type of behavior you are describing is typical of the failure of this sensor.

There is also a fan timer module which may be failing. This is what keeps the fans running after the vehicle is shut down. If the ECT sensor is good, this is most likely the culprit.

  • Thank you, I will keep this in mind after I take it to the mechanic and kind of cross reference it with that they say
    – Emad
    Commented Jan 29 at 19:26

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .