My 2004 Honda Civic is losing coolant and overheating. No visible external leaks, no water in oil, runs great, all new hoses, new thermostat, new radiator, water pump fine. It uses about 1 quart of coolant a week. When I shut the engine and even after it completely cools down, there is still pressure on the system. I can hear the pressure escaping when I take the cap off and the hoses are hard. It will not suck coolant back into radiator from reservoir. It has heat but not quite as hot as normal. What do you think?
Very weird cooling system problem help please
- Thread starter Avery4
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I'd get a coolant/hydrocarbon test kit, do a compression test, and start looking for a blown head gasket in general. Once you can confirm that is not the problem, move forward from there.
Head gasket. Fluid is being burned and going out the exhaust is my guess. ed
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Did you use genuine Honda thermostat, cap, radiator???
Yank your plugs and see if one is totally clean vs the rest? Water in the combustion will steam clean.
My 05 Neon came with a supposedly good-quality-from-factory MLS head gasket yet I had slow coolant consumption and a misfire on startup that cleared in 10 sec. Did the head gasket and it's fine now. Old gasket didn't look "blown", I can only assume something short circuited in one of the middle of the multi-layers.
My 05 Neon came with a supposedly good-quality-from-factory MLS head gasket yet I had slow coolant consumption and a misfire on startup that cleared in 10 sec. Did the head gasket and it's fine now. Old gasket didn't look "blown", I can only assume something short circuited in one of the middle of the multi-layers.
I've gotta agree: with that quantity if its not hitting the ground, you are burning it. either via head gasket or intake gasket.
did you replace the radiator due to a leak? did it overheat during that episode?
Originally Posted By: BigD1
Any coolant smell from the vents when the heat is on? Low coolant can cause heater to blow cold. Thermostat stuck open, or wrong temp rating thermostat can cause low temp heat too.
No coolant smell when heat is on.
Any coolant smell from the vents when the heat is on? Low coolant can cause heater to blow cold. Thermostat stuck open, or wrong temp rating thermostat can cause low temp heat too.
No coolant smell when heat is on.
I had a blown head gasket and my brother used this method to diagnose it.
We pulled the spark plugs and he pressurized the cooling system. Then he had a small light bulb on a stalk (like a grain of wheat bulb, it was a purpose built flashlight) that he stuck into the cylinder through the spark plug hole. This lit up the inside of the cylinder nicely. You could see the coolant pooling on top of one of the cylinders through the spark plug hole.
Of course this method depends on being able to sight into the cylinder, a "dental" mirror could help in some applications.
We pulled the spark plugs and he pressurized the cooling system. Then he had a small light bulb on a stalk (like a grain of wheat bulb, it was a purpose built flashlight) that he stuck into the cylinder through the spark plug hole. This lit up the inside of the cylinder nicely. You could see the coolant pooling on top of one of the cylinders through the spark plug hole.
Of course this method depends on being able to sight into the cylinder, a "dental" mirror could help in some applications.
First thing I would do is pull the plugs. If you are burning coolant you will have at least one real clean plug.
Originally Posted By: eljefino
Yank your plugs and see if one is totally clean vs the rest? Water in the combustion will steam clean.
My 05 Neon came with a supposedly good-quality-from-factory MLS head gasket yet I had slow coolant consumption and a misfire on startup that cleared in 10 sec. Did the head gasket and it's fine now. Old gasket didn't look "blown", I can only assume something short circuited in one of the middle of the multi-layers.
Ahhh, so that was the famous Victor Reinz HG issue? *My sis had an 05 Neon SXT. Said it was a turd. Looked kinda nice though, and was kind of comfy.. she got rid of it.
OP.. Car ever been overheated? ANY smells?
I sure hope it's not something internal to your engine. It sounds a lot like it is, though.
Pinhole leak...
Yank your plugs and see if one is totally clean vs the rest? Water in the combustion will steam clean.
My 05 Neon came with a supposedly good-quality-from-factory MLS head gasket yet I had slow coolant consumption and a misfire on startup that cleared in 10 sec. Did the head gasket and it's fine now. Old gasket didn't look "blown", I can only assume something short circuited in one of the middle of the multi-layers.
Ahhh, so that was the famous Victor Reinz HG issue? *My sis had an 05 Neon SXT. Said it was a turd. Looked kinda nice though, and was kind of comfy.. she got rid of it.
OP.. Car ever been overheated? ANY smells?
I sure hope it's not something internal to your engine. It sounds a lot like it is, though.
Pinhole leak...
We had a 70's Honda Civic which mysteriously kept losing coolant. Plugs looked fine and no coolant odor in exhaust. Evidently the head gasket leak was so slight the engine could burn the coolant. Then the gasket abruptly let go further and generated a cloud of coolant vapor when started.
All hoses? Even the heater and the little 5/16 ones behind everything? Those blow a lot
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