1994 Civic DX, auto, no ac, 91k miles. In case anyone is wondering I have just purchased, for my teen daughter, our 1st Honda and I know very little about what to expect. We have owned this Civic for about 500 miles. My current problem is when I am driving, once the car warms up the temperature needle will go up almost to the red then drop back to about half way ( which is where I think it should stay). It will continue this up and down fluctation for 30 miles, which is as far as I have driven it at any one time. It never has actually ran hot. It does not seem to matter if I am going 65 or sitting at a red light. I checked the water in the radiator when this happened the first time and it was low, I added appx. 1 qt to fill it. Tonight the fluctation happened again, the needle shoots up to almost red line then drops back to midway, checked the radiator level and it took about another qt., we have driven the car about 150 miles since the last time this happened. Once I fill the radiator the temperature needle hardly moves off the C (cold) in 30 miles.
The oil shows no sign of water and I have not noticed any steaming out the tailpipe. Is there a way to check the head gasket? Anyone have ideas about where the water could be going. Could it be boiling out the overflow when the engine temperature shoots up? I have not checked any fans or the radiator cap. The loss of water has me stumped, the car runs great! HELP

 

did you check where the hoses run towards the lower part? i remember when i took my radiator off and i put a new one back on the hoses fit but it would leak until i sealed it

 

You may want to replace your thermostat first if there are no leaks. Also check to see if the anti freeze is all going back into the overflow, if it is then you need a new head gasket.

 

check the radiator I had a high pressure leak in my radiator you only saw a leak when it was warmed up and has been running. If you do check the thermo. instead of pulling it off just let it get to oper. temp. and grab the upper rad. hose. if it is hot thermo. is working. the main thing is it is definately leaking you need to find out where.

Do not use stop-leak or anything like that unless it is an emergency. My shop teacher also said in an emergency you can crack an egg in the radiator to also stop the leak. if you carry eggs w/ you that is.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackflagracer93 &raquo;</TD></TR><TR><TD CLASS="quote">Do not use stop-leak or anything like that unless it is an emergency. My shop teacher also said in an emergency you can crack an egg in the radiator to also stop the leak. if you carry eggs w/ you that is.</TD></TR></TABLE>

I am pretty sure id rather have stop leak in my radiator than AN EGG!@!

You may have air bubbles in the coolant system. When the car is cold take off the radiator cap and start the car. Let it run with the cap off and keep filling it up if the level goes down at any point. Once the coolant heats up to normal operating temperature the level will rise - it is normal, put the cap back on. Make sure you have your heat on as well. This way coolant will also be getting into your heater core.

If this does not work then try a new thermostat. It is a simple install, just make sure you change the gasket as well to prevent any leaks. After you install the thermostat make sure you redo the bleeding process that I described above.

 

you can always get your car pressure tested at a radiator shop to check for leaks. if nothing is leaking, the order i would repair things:
- flush cooling system, bleed all air out
- new thermostat
- timing belt and water pump (if it hasn't already been done, should be done @ 105kmi)
- headgasket