I have a newer daily driver, its a 98 2 door civic DX. Good mileage out of towner car. I bought it about 3 months ago. I've been pumping the heat pretty heavy this winter, on my way home tonight (this is a first) it was near overheating and then the check engine light came on. I re-filled the radiator with water, 10 minute test drive with the heat cranked, seemed to be running fine again, probably need some rad.fluid? Whats strange to me though, I thought the check engine lights on newer cars (new compared to a chevelle) only came on at a certain mileage, seems like an odd coincidence. I need to go out of town, Sacramento to SF tomorrow so I hope its cool......... any thoughts would be appreciated.

Thanks........

Have your cooling system checked for leaks. Simple test, involves a hand pump and a few minutes of your time. The system should be able to hold pressure with no noticeable drop for 5 minutes minimum. Could just be a loose hose clamp somewhere.

or the electric fan not turning on.. and the rad fuild(antifrezze) being pushed out of the system...
thats why you needed to add..
have it pressure tested.. like said above..
it'll take 5 minutes.. but save you from killing the engine...
alum parts don't like overheating

I don't know much about newer Hondas, but the older ones had the worst engines ever assembled on this earth. They were guaranteed to blow the head gaskets, suck up the coolant into the engine and overheat. Yours could easily be doing something similar.
First leak check the cooling system. That will tell you if you have an external leak or an internal one into the engine.

Have your cooling system checked for leaks. Simple test, involves a hand pump and a few minutes of your time. The system should be able to hold pressure with no noticeable drop for 5 minutes minimum. Could just be a loose hose clamp somewhere.


Sounds good... I'll start here then, what do I need?



10 minutes and running heat on high, zero heat issues so far. Under the rad. cap the plastic is a little burned/melted around the rim. Im going to flush the radiator and refill with fresh fluids . It seems like it may be ok, it wont heat up now that I want it to though, Id like to see if the fans come on, maybe a dead relay?

I have 290,000 miles on my Civic. There are few things you want to check. First replace the thermostat and rad cap, they're cheap. Also, you can try bleed any air out from the coolant, I leave the rad cap off until it warms up. There a bleeder valve around the thermostat housing if you want to bleed it that way. Make sure the fan kicks on when you are up to temp. There are two sensors for the cooling system, one for your temp gauge the other for the fan. The fan switch can go bad. If your fan is not turning on, you can check the voltage at connector for the fan. Make sure you get voltage when you are up to temp if not your fan switch can be faulty. I leave the test probe connected and wait and see the voltage comes up when the temp needle meter just at half way point. If all this checks out, you may need to check the condition of the radiator. I had issues with overheating, not to point with a CEL or a boilover. I had to replace the thermostat one time and other my original 10 year old radiator just gave out. There is one last thing you want to check, there are close to 8 coolant hoses on my 97 Civic. They're a pain to replace. You may have a tiny leak around the intake manifold.

I guess you posted while I was typing away. Anyways, you need to have a voltmeter handy to see if your fan or the fan switch is bad.

I have 290,000 miles on my Civic. There are few things you want to check. First replace the thermostat and rad cap, they're cheap. Also, you can try bleed any air out from the coolant, I leave the rad cap off until it warms up. There a bleeder valve around the thermostat housing if you want to bleed it that way. Make sure the fan kicks on when you are up to temp. There are two sensors for the cooling system, one for your temp gauge the other for the fan. The fan switch can go bad. If your fan is not turning on, you can check the voltage at connector for the fan. Make sure you get voltage when you are up to temp if not your fan switch can be faulty. I leave the test probe connected and wait and see the voltage comes up when the temp needle meter just at half way point. If all this checks out, you may need to check the condition of the radiator. I had issues with overheating, not to point with a CEL or a boilover. I had to replace the thermostat one time and other my original 10 year old radiator just gave out. There is one last thing you want to check, there are close to 8 coolant hoses on my 97 Civic. They're a pain to replace. You may have a tiny leak around the intake manifold.

I guess you posted while I was typing away. Anyways, you need to have a voltmeter handy to see if your fan or the fan switch is bad.



Yeah mine is a 98, it has 168,000 on it. I flushed the radiator, refilled with antifreeze/coolant and water. Im going to pick up a new cap tonight or tomorrow, so these civics have 2 fans? One is on the radiator, one in front of the engine. When I turn on the AC/Defrost the engine fan comes on, I always thought the "cooling" fan was in front of the radiator, then in front of the engine. Who knows, I don't know much about Civics. But I havent done any electrical tests yet for the rad. fan, it didnt get hot enough to click on. Just a little confused. Do you know about the "check engine" light? Do those things come on when there is an actual problem as well as certain mileage? I thought it was on mile based....

my experience with honda, if they blow a head gasket, the car will run ok for a while, as long as it has coolant. but the coolant slowlly gets burned in to the combustion chamber. when the car starts to run low on coolant, then it will start to overheat again. it may take a few days for it to use enough coolant to start to overheat again. the head gasket is verry weak and will go at first sign of overheating. if your planning on a trip tomorow, just bring a gallon of coolant with you. (as long as you don't have bad leak, you should be ok) keep an eye for that guage, when it gets 3/4 way up stop and let cool, check coolant, refill if necesary.
the fan for the radiator is for the radiator, the other is for the a/c condensor. its only used for a/c.

I don't know much about newer Hondas, but the older ones had the worst engines ever assembled on this earth. They were guaranteed to blow the head gaskets, suck up the coolant into the engine and overheat. Yours could easily be doing something similar.
First leak check the cooling system. That will tell you if you have an external leak or an internal one into the engine.

Define older, I had an 85 Accord that went almost 200K without any problems except for power steering pump and an A/C hose before I gave it to my kids (they drove it 20K more then ran it out of oil and tossed a rod. My daughter bought a Civic new in 2000, it has about 180K with no problems. Both my Datsun 510 and Mazda GLC were the sensitive ones, both over heated once (blown hoses) and warped the heads.