My gfriend honda civic it acting up. It showed that it was overheating so I changed the gasket and thermostat because it seemed that no coolant fluid was circulating after having the car on for 15 minutes. The problem kinda went away for a while, but now is back again. the weird thing is that even when the car is showing overheating, I can remove the radiator's cap with my bare hands and not have a spill at all! (do not recommend to try this on your car). The cap remains at room temperature! The water pump belt looks fine, the water pump itself doesn't make noises, the fan seems to work good. No milky substance in the oil tank or white smoke. there seems like there are no leaks on the radiator or hoses and the coolant level is good. I am really stunt. Can someone help? I am starting to think that the water pump is not working or maybe it is just a temperature sensor even though there is no check engine light on. I will check the spark plugs for water, but really I am just running out of ideas.


Modified by pierre12k at 8:34 AM 9/12/2007

 

How long does it take to over heat? Sounds like you're getting no flow to the Rad. Colapsed inner hose or thermostat stuck completely closed. (It can happen even if its brand new.) How long has it been since the last coolant flush? If you've got floating particals they can plug things up.

 

Thanks for the reply.

I flushed the radiator before changing the thermostat. I know the thermostat can be plugged again, but I am not sure is that. both the top and bottom hoses can be easily squeezed and are not extremely hot when the car shows overheating. As for the flow, the coolant does not seem to circulate. One mechanic told me that some hondas are like that. (don't know if I am buying this though). Is the sensor in the thermostat housing the one that regulates the temperature gage? if not, which one is it? Also if any of this sensors are bad, would I get a check engine light on?

Overheating doesn't occurs all the time. for what I was told, it seems like it happens more often when the air conditioner is on.

I switched cars with her so I can play around with the car. I will drive the car for a few hrs and take it to the mechanic. I will post whatever I can find out later today.


Modified by pierre12k at 9:42 PM 9/12/2007

 

You're the first one I've heard of to have this problem. Hes right about the sensor though. There aren't to many things that can stop coolant from circulating, Even if the water pump is bad, coolant will still flow because heat rises.

 

if you can open the cap without it gurgling, psi is not building up. remove the radiator cap when it's cold, let the engine get to normal op. temp. see if the coolant is circulating in the radiator

 

so when its overheating (reading off the gauge) you can still remove the cap cause the cap is nice and cool?

 

Radiator caps can wear out, then it would not build pressure properly.

 

thanks again for all the replies.

I took the car to an experience honda mechanic and he is not sure why the car showed overheating. We let the car running for 30 minutes while increasing the rpm and nothing. the gage showed half way hot. The mechanic run a small test to test the circulation and the fan and both are okay. (he put coolant on a plastic container over the radiator and the cooland was sucked up and the radiator purged a little)

I believe the most logical answer could be that the sensor is not working properly, but isn't the sensor electrical meaning that it can only be bad or good and not sort of working okay? Am I right? He was really impressed about me opening the radiator cap after 30 minutes of the car running, and he said that it is the first time he sees that. hehehe me too.

One thing the mechanic did find is very little water on the engine. the oil cap showed minimal water. So little that the oil still do not turn white. (reason why I did not noticed it when I first checked it). Even with this finding, I am still stunt about the gage showing over heating when all physical checks showed otherwise (water hoses being soft, no pressure in the radiator, fan working properly, etc).

The mechanic pretty much told me that I needed to change the head gasket asap, and while they are at it change the water pump and timing belt because the water pump has never being change and it is now 166K miles! (did not know this until I asked my gfriend. she changed the timing belt at 90K but not the water pump). So pretty much the car needs a major repair, but I am not sure that will fix the original problem. I am afraid that when the mechanic opens the engine's head, more things will need to be change or adjusted and the cost will increase beyond my gfriend's budget.

This whole thing is a pain on the butt. I will take the car to a second mechanic tomorrow and see if he/she has the answer for the original problem.

I really want to know what is wrong with the car. it has become a challenge now. Once I find out, I will post the answer for all of you.