Hello im new to the forum and im looking for some little help with this problem. While driving my temp gauge on my 03 civic ex flucuates from half way to just below the "H" and at time over the "H".... Ive changed out the thermostat and also the senor on the block i believe it was the coolant temp sensor or swtich about 3 months ago. Im just trying to desifer if its a blown head gasket or water pump or something else related. I do notice that the radi fan turns on but doesnt seem that it stays on long enough to cool the engine, brings it down about half way between the "H" and normal operationg driving conditions. Any help would be greatly appreciated !!!

Thnx,
Art

 

First of all do you have enough coolant? Have you bled the coolant system?

A bad water pump would leak immediately and check to see if you have a milky substance in your oil. That will also help narrow it down if it was a blown hg.

 

Just checked the engine oil and no milky substance appears on dip stick, oil recently had oil change and they didnt point out anything at that time on the drain. The on the other hand does appear to be a little low now, and may have been for a little time b/c it has been going close to the "H" for past week now so that is low and when i changed out the thermostat i did not bleed the system, is that the roughly 1/4 dia hose adjacent to the cap? i did replace the cap when replacing the thermostat also. So im refilling the coolant now, can you explain to me the proper bleeding method? thanks again man.

Art

 

You most likely have air bubbles in your coolant system which will make your temp gauge fluctuate. What I do on my car is fill up the radiator, leave the cap off and turn on the car. Make sure your climate control is off. If there are any air bubbles in the system they will shoot out. Do this until your temp gauge is at normal operating temps. Once it's at normal operating temp shut off the car and top off your coolant again. Should be good to go. Sometimes it takes awhile so don't try to rush it and quit driving the car until you do this.

 

Thanks man its done and fixed ..seemed also as if i couldnt get the car hot enough to get the fan to turn on. There were quite a bit of bubbles i think the issue was when i changed the thermostat i was looking for a bleeder valve and when i couldnt find it i just kind forgot about it... but runs great now let it run for about 20 minutes and was justa bubbling away, Thanks Again,

Art