Ok, its an 86 civic, 1.5L, carb, and I love it. But I've been trying to hunt down this cooling problem forever.

I replaced...
Radiator
Water pump
Thermostat
Fan switch (fan seems to be working properly)

and it still overheated. So, I took out the thermostat, I know, it's not a good idea for the long haul, but it gets me to work and back now before overheating.

I don't have a leak, but the only time I lose water is if it starts to overheat and it boils over into the overflow tank, until that is full, then leaks out the top.

I can get it to take long trips as long as it's cold, and I keep moving

What else could cause this?

 

when does it overheat? while driving or while stopped? i am assuming "while stopped" due to what you said about keep moving.

 

Pretty good chance you have a blown head gasket.

 

i didn't want to be the guy that said it..

 

eh if the car is in good running cond otherwise id say its worth fixing.
Id pull the head, take it to a shop to see if its warped.
If not, tank/mill it and put a new HG in there. not that hard on these old cars.

 

it overheats regardless, it just takes longer while i'm moving, and when it's cold. it seems like it's just producing more heat than the cooling system's made to handle.

it runs great though. how can this be a blown head gasket? i have no water in my oil and no oil in my water either

how can a warped head cause it to overheat

 

What happens sometimes with a headgasket is it will break the seal and it will let hot exhaust gasses into the coolant flow. Thats whats causing your coolant to bubble like its boiling. Some of the coolant is making it into your combustion chamber and burning off, which is why youre losing coolant. If you continue to drive the car and overheat it you will eventually get the oil/water problems.

Its not the warped head that causes the car to overheat, at least at first anyway. The head on your car is aluminum. Aluminum, due to its properties, will deform under extreme heat like the car overheating. Once your head is warped, depending on the degree of damage you may need to replace it. And to answer your question a warped head creates small gaps between the head and block of your engine, allowing the hot gasses from combustion enter the cooling system.

 

That's odd. If the headgasket were breached, placing a higher load on the engine should make it overheat faster. Check for blockage of the radiator (AC condensor full of crap will do it) and make sure your fan is blowing strong. Over 35 mph the fan shouldn't matter as you have sufficuent aiurflow to cool the engine.


Still, with the coolant reservoir steadily filling up that's a classic symptom of a bad headgasket; the combustion gasses escape from the combustion chamber and pressurize the cooling chamber, causing it to force out coolant.

 

Wait, addendum. Does the car start funny when warm or hot? Is the powerband abnormally strong down low or up top, with the rest of the driving experience being blah? With all the overheating you might have done headgasket damage, but there's a good chance your engine is out of mechanical time aka "one tooth off"

 

bubbling in the overflow tank is almost always a HG.

 

have you pressure tested the cooling system?

 

my 83 overheated also. turned out it was a HG

 

Any luck with the problem?

 

Bought an 86 crx that was overheating... it was the hg on mine.

 

Sounds like HG to me also.... Just swap it out. Probably cost next to nothing and can do it in an afternoon. Pick up a manual for your car and go at it.

 

LOL when you replaced the radiator did it come with a new radiator cap?


i had the same problem.


it was the ****ing cap

the spring was gone and the rubber gone it made all the water go into the overflow tank, empty rad. boiled the water in the engine n gasses went from engine to rad to overflow n it looked like it boiled cos the overflow cap has a straw to the bottom.

 

Is your radiator fan running? Could be that you plug your fan sensor wires backward and cause your car to run hot and over flow.

You should give a reward for the person that solved this problem.....

 

Does your coolant smell like gas?