My 2003 Honda Civic EX has been overheating the last couple months. I replaced the radiator because it was leaking, replaced the thermostat, and replaced the fan switch. I filled it with antifreeze again. When I pull the ECT sensor and wait, neither fan comes on. Although, the fans have come on when the car gets hot. I jumped the motor, that’s good. I checked the relays, there good. Anyone know why the fans don’t come on when the ECT sensor’s unplugged?? Should’ve come on almost immediately. I’m pretty sure the sensor’s still good. The engine reads cold when unplugged, and it reads warm when plugged back in.

 

Why would a fan come on, when the engine is reading cold? How far up the gauge does your temperature read? Do you have a more accurate temperature sensor reading from an OBD2 scanner or readout?

 

hey, thanks for the reply. i haven’t checked the temperature using a scanner. the temperature gauge used to red line, now it reaches about halfway between the middle and red lining before i turn the engine off to cool. frequently, i turn it off and right back on, and the temperature gauge will have already dropped a few notches, which is strange. & to answer your fan question: that’s a good point. i was only taught that the fan should come on automatically in response to the ect sensor being pulled.

 

If your car is overheating rapidly, you may have a blown headgasket. Its a rather common problem on these engines.

 

what does this mean ?

 

Engine Coolant Temperature sensor was disconnected... I'm guessing.