EG overheating strangely

Hi all, i have an EG Sedan now as well as the LS.

anyways, the EG over heats but not like the other ones i seen when i done the search.

i took it to my mechanic and he fixed up the thermo switch because the fan wasnt cutting in. that was all sorted and he made me a bridging wire just incase. he said there was an awful amount of pressure in the system and checked the level, which was fine.

anyways what happens is, when i leave the engine to idle, its fine, but when i start driving, it creeps up, i pulled over, checked that the fan spins, it does, so i bridge it anyways to make sure that the fans on to see if it could be anything else.

drive off, turn air con on while driving at night when its cool, over heats. pull over, pop hood, fans spinning, turn air con off, idling and then cools down, put the heater on free flow, air con off and finish the rest of the drive home, the engine temp sits a little above halfway.

i asked my mechanic when i get home, he said it sounds like a failed thermostat. I asked him if there is soo much presuure in the cooling system, could it be the water pump? but he said unlikely, must be the thermostat.

alot of people here have stated theirs has crept up when stuck in traffic, mine creeps up when im driving. so my spirits are kinda dampened until i find out what it is!

AFAIK , if the water pump failed- there woudl be too little pressure in the coolign system.

Soudsn to me , like a new thermostat - it sounds like it has freezed in the closed position , thus not letting the coolant flow completley thru the engine after heated up etc.

A new thermostat is like $50 - easy to replace too.
Get it done ( and flush your coolant/replace with new stuff) and then see if that corrects the problem.

If its still there...might even be a headgasket issue ( $$$)

I recently had a very similar problem.... thermo

bennjamin, we are doing the thermo and coolant flush tommorow, mechanic suspects air in the system, so we gonna do a bleed and thermo tommorow.
he says that the thermo is working, probably just not opening up fully.??????

as for head gasket, one of the common signs is milky residue under the oil cap. theres no milky stuff there, no white smoke getting out of exhaust. no idling issues. just over heating. though it does not over heat to red, just 3/4 way

Proecu, did yours rise up when you were idling or driving?

hell yea its ur thermostat, like bennjamin said, it's probably stuck in the closed position. Happened to me not long ago. Get a new thermostat before u blow ur head gasket...

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Proecu, did yours rise up when you were idling or driving?

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idling was slightly high but would be lower than when driving. So when I was stationary at lights, it would come down, & climb when driving.

Test this, drive with Heater on FULL. Temp should decrease.

In any case, replace the thermo and go from there. It's a 30minute job, less if ur good.

You can test the old thermostat by boiling water at 100deg and place the thermostat in it. If it doesnt open, thats the culprit.

turned out to be the thermostat afterall.

the gasket was worn and the inside was tilted to one side, making the thermostat partially open and fully open or in other words just stuffing around with the flow.

works a treat. Mechanic said that the people i bought it off replaced the radiator because they thought it was causing the problem and still overheated so their dodgy mechanic probably told them to sell it off quickly and flushed the cooling system and put new one in to see if it will hold it self temporarily and sell it to an unwarey buyer.

i reckon whoever picks up an EG or other civic should change the thermostat first thing because it seems like a common problem???

thank you all for your help, the head gasket is fine :)

how does it run in general after the thermo replace ? alot of difference etc ? Im about to DIY replace mine...jsut wondering if it will change all that much runnign wise really...

well you can pelt it more and the car wont heat hard, thats all i can think of.

bennjamin, its not hard at all to replace at all, mechanic did it in 10 min

yeah is just 2 bolts, unscrew
take the old one out and put the new one in. put back screw
and do a radiator flush at the same time.

your car temp will never go up or down again.