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HELP. 2004 Honda Civic Overheating

Car overheats when driven for about 20-30 minutes. Have replaced radiator, water pump, timing belt, thermostat, radiator cap. There is a crack in the manifold, and at times the motor for the ac won’t come on and then will randomly kick back on. The heater runs really hot as well. I’m thinking the ac condenser may be my next/final step before looking at work on thw head gasket or a jdm motor swap. Any advice on how to trouble shoot these problems? Are they related? Any help much appreciated I feel at my witts end with the car currently.

Look thru the grill to see if the condenser has debris covering it.

If it does, use a shop vac with a brush to remove it as it’s easier than trying clean it from behind.

If the condenser looks fine, when the engine is cold, remove the radiator cap.

Start the engine, and as the engine idles watch the coolant in the radiator.

If bubbles begin to form in the coolant, that’s an indication of a blown head gasket.


Thank you I appreciate the help, I’ll give this a shot when I get home from work this evening. Spent my lunch break trying to figure out what my next step is. Will post what I find after doing this!

Have you checked to see if the electric cooling fan turns on? If it doesn’t the car will overheat in traffic but may be fine on the highway.


The engine in this Honda is great, the head gasket is not. Very typical to have overheating as a symptom of a bad head gasket with this era engine. If you get it checked and fixed quick enough you will get a lot more miles out of this.


Yes we checked and the fan does turn on. Its odd because at times the vehicle won’t overheat until once we get off the hwy and are in city traffic, other times it starts to overheat while still on the hwy. Definitely has us confused

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The problem has been ongoing for a few months now with us repeatedly fixing more and more parts, I’m hoping that if it is the heads we can still fix it and there isn’t lasting damage from how long of a process it has been identifying the problem. I’m wondering at this point if it would be a better idea to just swap the motor? Don’t want to spend such a large amount fixing the head gasket and end up having to swap the motor a few months down the line after all due to damage. We have put quite a bit of money into the car in comparison to its value at this point unfortunately, trying not to continue digging myself too large of a hole… Is there a way to evaluate this option properly in terms of damage?

Have you tried what Mr. Tester posted ? He is one of the people who post here that gives excellent advice .

Not yet I get home from work in a couple of hours and I’m going to give it a shot as soon as I do. It is definitely excellent advice. If it is a head gasket issue hopefully too much damage hasn’t been done with how long the problem has been occuring to replace and save the motor

@Tester removed the radiator cap and turned the car on, large bubbles slowing forming one at a time rising and popping causing the level of the fluid to fluctuate. About 4-5 rows of fins on my condensor are flattened


You messed around with the cooling system. So there might be air still trapped in the cooling system.

Drive the vehicle around the neighborhood until comes up to operating temperature and redo the test.

If bubbles appear in the cooling system again?

That’s a pucker factor of ten.


That’s a terrible idea, in my opinion

Any jdm motor . . . a used motor, I presume . . . might already have a blown headgasket, or may have one soon after you install it

Used parts are a big gamble

head over to napa and buy this kit. It’s really easy to use. If you use it properly and the fluid turns yellow, chances are the head gasket is a goner

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We’ve had it burped twice… Will drive it around until the temp is up and check it again


Don’t remove the radiator cap until the engine is cold.


No definitely not I don’t like to gamble with used parts everything we put on is new, especially if we go the route of a motor swap would definitely be new. I’ve priced them out and not too bad but I was hoping not to have to do it if I could get more life out of the motor. I’ll Definitely head down and buy one of those block tester kits and give that a try

My guess is the head gasket. But it could be something really simple too, like the radiator cap isn’t holding pressure. So before doing any work on the head gasket, make sure the basic tests have been done, including a cooling system pressure test, including the radiator cap. If you feel lucky you could just replace the radiator cap. Overheating after driving on the freeway and then slowing down for surface street driving can be a result of the cooling system not holding pressure. Not holding pressure isn’t necessarily a head gasket problem. Make sure when it is overheating that the radiator fans are spinning like crazy.

The vehicle is at 210,000 miles and haven’t had any major repairs before this besides swapping the clutch so I was anticipating something else to go wrong eventually

Cooling system pressure test was done twice as well at pep boys, came back good. And radiator cap was also replaced as well…

Looking more and more like a head gasket problem. Did it ever seriously overheat before all this started to happen, maybe even years ago, like b/c the radiator fans stopped working or it ran low on coolant?