I've searched but found no answer.
1999 civic ex automatic
I have checked the fan fuse, relay and thermo switch.
It has a new thermostat.
When i jump the two wires on the thermo switch the fans would stay on.
Car is not smoking at all.
Wierd thing is, when i drive around for 20 mins the temp gauge stays above half way, fan not on, and when i open the radiator cap, there is no pressure. any input would help. thanks.

 

I had that issue before. What I did was unplug the 2-wire pin at the thermostat, and jumped the two wires so that the fan comes on whenever the engine was on. I know...it's a bandaid to an issue but I was never able to figure it out either. Perhaps, the thermo switch is staying in "open" position. Just like any sensor, it can go bad over time.

 

Fan switch maybe...

 

^^^ more than likely since jumping the wires do turn the fan on.

 

Yeah...Same problem with my old coupe...no fan...was able to jump it with a paper clip and finally ordered a fan switch off ebay and it fixed the problem.

 

So i jumped the fan switch and drove around for about 30 mins and the temp gauge is still staying above halfway.

 

The temp sensor is on the side of motor....single wire underneath the distributor. The one wire rubber "bullet" plug is what you are looking for.

 

Is this car turboed?

Wow so you jumped it and the fan still did not bring the temp down, so that means even if you do the fan switch it will not help.

A few things, make sure you are not low on coolant.

Have you bleed the cooling system, might be air.

Since it is constantly high, could be a bad water pump, maybe radiator.

I would pressure test it.

Last resort headgasket.

 

car isnt turboed.
coolant is full
how can i tell if its a bad water pump? I notice when the car is up to temp and with the radiator cap off. i dont see the coolant flowing. Is it supposed to be bubbling?
I dont think its the headgasket because theres no smoke coming from the exhaust and im not losing coolant nor oil.

 

i had the same issue. then i swapped out the motor and noticed it had the same issue...? well i learned that it was my radiator cap.

try replacing it. and it should work. cuz it seem that your fan is good, temp fan switch is good and thermostat is good.

it has to be the rad cap. it will give you those side effects when it goes bad.

please come back and post if it worked. good luck.

 

If you do not see the coolant flowing could be a bad water pump.

Was the water pump ever done, or recently?

By the way do not drive it at 3/4 for too long, still way hotter than it should be.

 

does your lower radiator hose get hot?

 

yes lower radiator hose gets hot. so i know the thermostat is working. im going to try a new radiator cap first. I dont think the water pump was ever changed.

 

yeah replace the cap. i wanna know if that helped you out. I have two other friends that had the same issue and i told them the same thing and .... wallah

 

If you run it without the cap and see no movement chances are it is more than just the cap.

 

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push/turn the dash heater lever/**** to MAX heat. Fan need not be on.

3) Follow the directions in the diagram below

 

heres a video. i did what you said. cap loosen, front end higher than rear, heater on blast, this video is with the cap off and at operating temperature. fan never kicked on. temp started to rise above halfway.

http://youtu.be/xpm9icmDwYQ

 

It doesn't seem like it flowing, like I said before might be water pump.

 

Can the water pump be that bad to not circulate the coolant? I just bought a new radiator cap today so going to test it see how it goes.

 

Yes, how long have you had the car? Any record of the timing belt done? As you know when you do the timing belt you do the water pump as well.

 

i just bought the car. No record of timing belt change.

 

Same thing happened to mine. Try connecting a ground from the fan's relay directly to the battery.

 

new cap doesnt work. same problem. fan doesnt kick on and still overheats. Im starting to think it is the water pump.

 

well the fan is running right now but its being jumped at the fan switch but it still overheats. needle Stays just above the normal operating temp.

 

If there is no flow, then it is most likely the water pump.