ironryder

hi all,i know there is lots of overheating issue but i can't find any answer when it only happens in traffic,and if i turn on the heater fan,temp goes back to normal.so what could be the cause?
here is the deal with my car. 98 civic EX,new oem water pump and thermostat last year, one rad hose went last month(one the goes from the block to fire wall) after i replace it, i fill the system, let the car run with rad cap off till i see no more bubbles.

fv8s

Bleed the cooling system the proper way. Car up on jack stands, heat on HIGH... repeat this several times. I would also consider a leak down test.

dpetro1

sounds like a fan issue to me. make sure the system is bled properly (idle with cap off until fan cycles on/off twice). if the fan isnt coming on then you can start to test the system including the fan switch, relay, and fan itself.

oldnose

I agree with this. Had a whole fan go out once, quick volt check of the wires confirmed it.

Also, theres a bleed screw on the upper radiator hose that helps a little with bleeding, its not necessary though.

ironryder

thanks all,my relay and fuse is good, now im thinking is my fan switch...where is the fan switch? i can't find it in the manuel

fuzzman

screwed into the thermostat housing

itsnotfast

x2 on this.

This could be alot of things including a bad head gasket. I would start with bleeding the cooling system. I would definitely recommend a leak down test.

ironryder

how do you do a leak down test? do i have to bring it into a shop?

dpetro1

diagnose your fan problem first. as stated above the switch is located in the thermostat housing.

thread jacker

I call air in the cooling system

sextav6

take a paperclip and jump the fan switch to see if it kicks on. had the same issue recently

EL Vap133

#12 in this diagram

alacard

Sounds exactly like my fan switch problem. Bleeding the system is extremely easy to do, so you should really try that out first.

ironryder

thanks for all your help. new up date.last week,i jack up the car with rad cap off and idle for like 30mins the fan never kicked on nor it over heat, maybe is too cold now? is like 20F around here now.but i notice after i shut off the car i can hear bubbling sound,like water boiling.
few days ago during morning start,it was miss firing,idle low wanting to shut off. until the car fully warm up than it stop.that only happened once.parking out side on a down hill.
today after driving about 5 min,it starting to over heat,i turn the heater fan on high than it came back down.but it was still fluctuating on the 20 min drive home.after im at home i notice the fan is not on even with high temp,shut the car off,turn it back on..than the fan kicks on...wtf? so the fan switch is not recognizing high temp?
pull the codes, 302- (that was the miss fire) 420-( have this before the over heating) 1399?- (can't find that code or i wrote it wrong ?)

mattyfo0z

Did you fix your fan issue? If you're fan's not running, that's probably why you're overheating.

You entire situation sounds really similar to mine. Although, I never overheated - my radiator/overflow just started bubbling and steaming in stop and go traffic. I realized my fan never turned on, so I jumped the plug that goes into the thermostat and have had no problems since.

JDMpride

fix the fan

ironryder

the fan do kick on,but is just wayyy too late...after is already over heating.is there some type of temp setting sensor of some sort for the fan?

Former User

I'm thinking the head gasket is possibly blown. Try cylinder compression and leak down tests, as well as pressure test the cooling system.

ls_turbo50

fan running? 1st thing i would check n if not find out why

Jimster480

Just jump the fan. Thats what I did in my car yyears ago to quit having issues like this. just get a paper clip or a small wire and jump the terminals. then the fan will run as soon as you turn the ignition on. Then see if your overheating problem goes away. if it does you can get a new sensor or you can just leave it like that.

aka red

get a temp gun to see if the coolant if flowing correctly threw out the radiator. you may have more than one problem with the cooling, bleed the system again do a pressure check then do a block test. did you put the right thermostat on .