Can anyone please help me with my temp problem. I have a 94 civic dx coupe.

When driving short distances the temp needle will be fine about 1/3 high.

When driving on the highway for 30 km or so the needle stays pretty consistent at 1/3 too.

Now when driving for extended periods of time (ie 20 mins+) on the highway and then coming to the city and idling, the gauge would start going up to about 1/2 to 2/3. It will go back to the regular 1/3 level sometimes out of nowhere but then back up and maybe back down. sometimes i'll drive some more and it will settle but sometime it will go up to 2/3 again.

I noticed when driving in the city or when idling the temp gauge tends to go up more frequently than say driving on the highway.

I don't visually see any coolant leaks but i hear a blown head gasket could burn the coolant. I did replace the radiator a year ago so I doubt its a faulty rad.

I initially thought it was the thermostat cuz i got a rad flush and the coolant wasn't really flowing to smoothly but after replacing the thermo and the rubber gasket the problem still occurred.

I have 2 more hunches. 1) The rad fan isn't working 2) the head gasket has gone bad. What are the symptons of each one?

Here's my questions though. I know the rad fan doesn't go on so should i replace the fan, the belts or the temp sensor which tells it to turn on? How much will each component cost? What's that second fan close to the rad fan?

One time I turned off my engine after the temp gauge was going up. I turned the car back on 5-10 minutes later and a lot of white smoke came out the exhaust. Is this a sympton of a blown head gasket? How much will it cost to replace the gasket?

Thanks everyone for your help. Much appreciated.

 

Well in most cases of a head gasket you will not only burn coolant but also oil. One way to tell if it is a head gasket is if it is making a "STI" exhaust sound then its a head gasket.

There is one other thing is that there might be a air pocket in your cooling system. Theres a bleed valve where the upper radiator hose meets the head. Open it up slightly to where a tiny bit of coolant is coming out and let it come to runnig tempand once the thermostat opens it should circulate and the air pocket will be nomore. Then just top it off and there you go.

 

is your fan coming on? if not then its either a fuse or your thermostat is bad.

You run cooler on the highway because of the added air going over your radiator. If you must drive it around put the heater on max, that will help out a bit.

To check if its your fan start it up with the hood up and let it idle. Once it hits about 180 degrees (usual point of activation) or about 1/2 way up the gauge the fan should kick on. If it doesnt then thats your problem. Check my first line above if this is the case.

ADDED: white smoke sounds like a head gasket or a broken/leaking tube... if it is the fan check the fuses first. If thats not it I'd almost bet money that its the thermostat... but could just be that the fan took a crap on you too.