I have a first gen b16a head on ls bottom in my 91 civic si. When i got the car for some reason it started over heating when i stopped, and went back down when i drove. It would also go down when i turned the heat on. I searched and found that it was probably the thermostat. So i replaced it and problem solved. Now a year later i swap out the block and change the thermostat just because it was out already. But it didnt have that little ball on it to show which way was up. So i put it in and after driving it around it started over heating when i stopped and would go back down when i drove and also turning on the heat. But it wasnt always. It was every once in a while it would over heat. I guessed it was the thermostat being in wrong and i was right. I bought a new thermostat with a lower heat range. I put it in with the ball pointing up. I figured it was problem solved. But the next day i drove it around and when i stopped it started over heating. I read some where that it might be the radiator fan switch, but im not sure where that is, how to take it off, or if that is the problem. Does anyone have any ideas? Thanks

 

???

 

anyone?

 

lets start with does the fan come on?

 

Well, i think. Im not sure. It happens only every so often. Ive let my car sit before to see what happens but it doesnt over heat. Its very random. The one time i let it sit and wasnt paying attention it over heated and my gf shut it off before i could see if the fan turned on or not. and when i started it again it was fine.

 

theres a coolant temperature switch next to the thermostat housing. its a two wire clip. umm dont think theres any others around it so it should be easy to find. and do you still have ac or no

 

no ac.

 

also it could be that theres a bubble in the coolant system that is causing the thermostat to not function right. you might want to bleed out the system and check it again.

 

ill try that. But would that make it so sporatic like that. There are no special conditions that make it over heat. It just does it at random.

 

thats exactly what a bubble will do. it just wonders around in your coolant system until it works its way back to your thermostat and then "BAM" t-stat closes. then you get the coolant moving again and it goes down and so on and so on

 

well the temp only goes down when i start driving or if i turn the heat on full blast

 

look do this, drain out the coolant from the little plug under the radiator, put the plug back in, take off your cap while draining, it makes it go faster, then go start the car with no coolant in it, then start pooring in the premixed stuff or mix it correctly, and just keep filling it up tell it gets full, then wait for the t-stat to open it will suck it all down then add more while its sucking it down. check the temp gauge to see if its normal, then go drive around and watch it and if the problem persists then continue the process of elimination, thats the best way to find the problem. if this doesnt fix it

check your
fan
fuses
relay
any hoses leaking
proper mixture
fan switch
temp switch
gauge cluster (yes your needle can break)

thats pretty much everything. (correct me if im wrong) thats all you do to fix something is process of elimination, just gotta get everything in order, lol good luck man, i know its annoying as hell. but im pretty sure its a bubble.

 

thanks for the info. Its been realy helpful.

 

the radiator fan switched should be to the left of the radiator cap.

 

really? I thought it was on the thermostat housing?