I HAVE A 1990 HONDA CIVIC WAGON AND IT KEEPS OVER HEATING.IT IS NOT LEAKING ANYTHING AND I PUT A NEW THERMOSTAT IN. IT HEATS ALL THE WAY UP TO THE H AND THEN DROPS BACK DOWN JUST AS IT GETS TOO HOT. I HAVE BEEN TOLD THERE IS A HEAT SENSOR.WHERE IS IT AND HOW SHOULD I CHECK IT?AND ANY OTHER HELPFUL ADVICE WOULD BE GREATLY APPRECIATED

 

are you sure that your fan is functioning?

If you drive on the highway and the temperature cools down but city driving overheats, it's probably the fan/fan motor.

Otherwise, have you done any collant system work recently? If you did, you have to bleed the coolant system, A LOT. Any air in the system will cause the motor to overheat.

I'm sorry but I am not familiar about "heat sensors." I thought that the thermostat was the heat sensor.

Good luck!

 

THANK YOU I WILL INSPECT MY FAN. GOOD POINT ON THE THERMOSTAT! DUHH! IT SOUNDS LIKE MY FAN.

 

Actually, there's two temperature sensors on the engine - one is the Intake Air Temp sensor (on the intake manifold), and the other is the Coolant Temperature Sensor (located close to the thermostat. The CTS (probably not the exact term) tells the ECU when to turn on/off the fan (as well as supply information to the dashboard gauge). If the temp gauge is working, the CTS is most likely working.

Check the CTS (make sure it's plugged in - hasn't wiggled itself loose or anything), and then check the fan and all wiring leading to both. There's also a fan relay in the underhood relay/fuse pod - check it as well (unplug it, inspect the blades for corrosion and the casing for distortion from having melted, and reinstall it). If you have another relay of the same flavor, try swapping the two and note the results. If nothing changes, swap them back (just in case).

I've heard of the need to bleed the cooling system as well, although I've never experienced it (actually having to use the bleed valve by the upper radiator hose on the block itself).

Start the car (with the engine cold) and take off the radiator cap - make sure the radiator's not being sucked dry when the thermostat opens - if it does, you're low on coolant and topping it off should make a huge difference.

Make sure you get this problem tracked down and solved ASAP - warping the head can occur if the engine's run too hot too much, and it will most likely pop the head gasket in the process, along with all sort of other bad stuff. You don't want to let this persist too long. That's how I got my '95 Hatch for only $800.

Hope this helps.

 

ya check those and ALSO check your CAP LOCK button on your keyboard

if youve done any work to the car lately say so...... will help run the problem down..

 

Before 1992, the temperature switch that controls the fan is screwed into the back of the engine block near the oil filter. It is the sensor with two wires, the one with one wire is the oil pressure switch.