im having a problem started a few months ago. my engine temp is registering as Hot, i mean the needle sometimes gets super high but then drops down to about mid range , it does this over and over again
Registers as hot for about 5-10 min then drops down again to normal. ive replaced the thermostat and still nothing. i was told it might be a bad temp sensor. i have a new one but havnt installed it yet. sometimes i would fill the radiator and it seems like it would help keep the engine at normal temp . then after about 1-2 weeks i would have the temp rising again, weird thing is i tried filling the overflow for the radiator to full after i drove it of course and after a week i would check it again after i drove it and it would be pretty much empty and my temp would start rising again. any ideas on this?

 

Does your fan turn on when it begins to get hot?
Are you loosing any coolant from the system?

 

ya fan works fine and theres no noticible coolant leaks anywere. im thinking it may be sensor related if its rising then falling back to normal. started acting up again tonight to. Im gonna flush the coolant to and see if theres any air in it

 

You can check if the sensor is working. The sensor sends a voltage back depending on the temp. The temp is a thermoster so as the temp changes, the thermoster changes its resistance. The higher the resistance, the lower the voltage bieng sent to the ECM or gauge cluster. If you get me the year, trim, engine, etc I can try and look up the voltage/temp map for you. To get the air out of the coolant system, you can bleed it just like the brakes. The bleeder screw is located on the themostat housing.

 

The replacement of the ECT switch takes 10 minutes and costs $15. Since the cost of an engine is considerable more,I recommend changing the ECT switch. You have not provided anytrouble shooting that you may have done and that would be helpful in diagnosing the problem.AHaynes manual will walk you through most of the basic trouble shooting. Good luck!

(let us know if you need assistance changing the ECT switch)

 

if your rad & overflow are empty when you check them, theres gotta be a leak somewhere. might also be your water pump..it would be hard to see a leak there. also could be your lower hoses or the coolant could be evaporating before you see it. id recommend getting a pressure test to try and spot the leak.

mine (95 civ auto) had the same symptoms ... turned out to be water pump, rad cap and thermostat.

 

Yeah if your radiator keeps becoming empty it's either leaking out or getting blown out by pressure from a leak inside the engine (head gasket).

 

well ive filled my radiator and bled the valve looked like there was some air in the line saw some bubbles coming up. now i dont have any problem with it. temp stays right under the half way mark on the gauge. still need to get a flush though. and also. VIP has a special for this run-rite stuff to clean up my engine. would it be worth it you think?

 

I have a similar problem with my civic DX 93. How much it suppose to cost a pressure test? And what they are checking (pressure of all system, pressure of cap, radiator fan)?

My car problem is:
When I use the heater (no A/C), it smell like coolant. I have to fill the radiator once in a while same if the reservor is full must of the time...When I'm a long time in town (stop in traffic or at too many lights)the temperature go up but when I start driving again it go down...

Thanks for your help!

 

remove the therostat valve