My 2003 honda civic with 140.000 has been overheating

I've had this car checked out by a mechanic and the thermostat was replaced had a pressure test to check for air pockets, nothing. Had a test for a bad head gasket with some sort of chemical test which came back negative. But the car still overheats. I was told by this mechanic that there is a pinhole-sized leak in the head gasket somewhere that leaks into the engine very slowly.

I have to drive about 60mi every day and as I drive at high speeds the car is fine it doesn't overheat. It's only when I am at idle or driving slowly that the gauge begins the rise. On these daily trips I have the heater blowing the entire time because I know it acts like another fan to take heat off the engine. But when I am at a red light all the sudden the air which is on the hot position will turn cold and then the gauge will start to climb. Is this normal for a blown head gasket? or when the coolant gets low. By the time I get to my destination is the coolant is basically gone and it's about the same time I am close to my destination that the air turns from hot to cold and overheats.

Also, this more after my 60mi drive it overheated and I looked under the hood and saw that coolant was sprayed all over the air intake and downwards below of the overflow could the overflow be spitting all the antifreeze out?

Thank you

  • Please don't open a new question which is essentially the same as your previous question. It isn't going to help you solve your issue any better and only confuses people. Commented Jan 28, 2015 at 21:19

1 Answer 1


You have a blown headgasket. It's slowly sucking your coolant into the cylinders and pushing it out as exhaust. My Subaru Forester did exactly the same thing two months ago and I ended up with a $3000 repair bill for headgaskets, timing belts, etc. I also had a negative carbon monoxide test (the chemical test you mentioned). There wasn't any white smoke, it just sucked up coolant and overheated after a long trip.

If you need more proof, take off the radiator cap when the car is cool, then have someone start it and rev it up. If the coolant in the radiator rises up or even spills out, you have a leak between the cylinders and waterjacket. Let the car warm up until the fans kick in. When that happens, you should see a stream of tiny bubbles coming up into the radiator (when the thermostat opens).

The reason your heat goes away is because there is no coolant to transfer heat to your cabin.

Just have the head skimmed and a new gasket installed. This isn't going to get any better. And for your own sake, don't use chemicals to plug the hole, it will just end up clogging things that really shouldn't be clogged. I know it's going to hurt your wallet, but it has to be done.

  • You should also consider that your car is 16 years old. A water pump has an inner disk with fins that rotates and forces the coolant through the system. When a water pump fails it is usually the fin disk bearing, or the Fin disk itself (sometimes the fins on the disk rust out and wear down and decrease the force of fluid flow. You will get better flow if the car is in motion because that's when the disk is turning faster as a result of acceleration but stopping at a light and slow driving behind traffic is when it will begin to heat up again. Replace Water Pump. Commented Jan 3, 2016 at 8:35

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