My 2004 Honda Civic just started overheating intermittently. The first time it started showing signs of issues was running a couple marks hotter than normal while driving on the highway. Almost at half. I stopped and checked coolant, which was full. Then the temp got to 3/4 while still moving. I stopped and checked oil and coolant. Both were full. It did not overheat again for a couple of days. But when it did, it was at idle. It got to 3/4 again. I turned the heat on and it kept going up. Heat worked. I pulled over and let it cool down. No steam. The overheating is not consistent or reproducible. It has no thermostat, new radiator cap, burped radiator, radiator flushed, cooling fans work, heat always works and it overheats more with air conditioning on. I can see coolant swirling in radiator with engine running, so water pump works. The car does not leak coolant, but it squirts out of the reservoir when it overheats. Any idea what is wrong with it?
Car intermittently overheating. Pease help
- Thread starter Avery4
- Start date
- Status
I'm still guessing waterpump acting up. How many miles are on car. Maybe a sensor is acting up? Have you had obd2 checked for codes?
Originally Posted By: Marco620
I'm still guessing waterpump acting up. How many miles are on car. Maybe a sensor is acting up? Have you had obd2 checked for codes?
It has 110,117 miles on it. I will put the new temp sensor from my 2005 Civic on it. When I removed the upper radiator hose and ran it for a few seconds to see if it pumped coolant, it pumped a normal amount. No OBD codes.
I'm still guessing waterpump acting up. How many miles are on car. Maybe a sensor is acting up? Have you had obd2 checked for codes?
It has 110,117 miles on it. I will put the new temp sensor from my 2005 Civic on it. When I removed the upper radiator hose and ran it for a few seconds to see if it pumped coolant, it pumped a normal amount. No OBD codes.
Last edited:
Is the radiator partially blocked?
Get a temp reading gun and check radiator for cold spots, I'll bet it has sediment in it that flushing won't get out.
As soon as you shut the car off, put your hand on different areas of the radiator to check for hot and cold spots. If there are major variations in temperature, you need to work on your radiator.
I would put a new tstat back in.. how long has it been out and have you run it without it b4? it could be circulating the coolant to fast.
fast moving coolant flow could also mean larger temp swings at your temperature sensor
fast moving coolant flow could also mean larger temp swings at your temperature sensor
Last edited:
Originally Posted By: Texan4Life
I would put a new tstat back in.. how long has it been out and have you run it without it b4? it could be circulating the coolant to fast.
fast moving coolant flow could also mean larger temp swings at your temperature sensor
I did not run that car without one before, but I did run another 7th gen Civic(my 2005)without one before, and it ran a couple marks above ice cold. It never got above 1/4 on the gauge.
I would put a new tstat back in.. how long has it been out and have you run it without it b4? it could be circulating the coolant to fast.
fast moving coolant flow could also mean larger temp swings at your temperature sensor
I did not run that car without one before, but I did run another 7th gen Civic(my 2005)without one before, and it ran a couple marks above ice cold. It never got above 1/4 on the gauge.
According to the images I've found of a 2004 Honda Civic Thermostat it has the stopper on the back of it that blocks off the recirculation passage in the head as the thermostat opens.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
Originally Posted By: Brad_C
According to the images I've found of a 2004 Honda Civic Thermostat it has the stopper on the back of it that blocks off the recirculation passage in the head as the thermostat opens.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
I took out the thermostat BECAUSE it was overheating. Thanks for the help. I will put a thermostat in and report back. But if that is why it is overheating, would it not do it consistently? It was overheating from the day after my aunt gave it to me.
According to the images I've found of a 2004 Honda Civic Thermostat it has the stopper on the back of it that blocks off the recirculation passage in the head as the thermostat opens.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
I took out the thermostat BECAUSE it was overheating. Thanks for the help. I will put a thermostat in and report back. But if that is why it is overheating, would it not do it consistently? It was overheating from the day after my aunt gave it to me.
Originally Posted By: eljefino
Take off your hood for more airflow.
lmao, brilliant
Take off your hood for more airflow.
lmao, brilliant
The thermostat just makes it reach it's maximum temperature sooner. 99.9% of the time, especially on a computer car that's what you want.
You are not doing any favors by running it without a thermostat. Especially if it often does not get up to temperature. It's going to be running real rich and getting worse gas mileage.
You are not doing any favors by running it without a thermostat. Especially if it often does not get up to temperature. It's going to be running real rich and getting worse gas mileage.
Steps to take IMO:
1. Install thermostat and test run a couple days. If problem continues:
2. Radiator has enough scale/crud to reduce cooling capacity on hot days, so replacement is a good idea along with a coolant change.
I've seen enough cars that were fine in the winter and start suddenly overheating when it gets hot outside...without exception they needed a new radiator. At 11 years old if you haven't ever replaced the coolant, your cooling system is sludged up.
1. Install thermostat and test run a couple days. If problem continues:
2. Radiator has enough scale/crud to reduce cooling capacity on hot days, so replacement is a good idea along with a coolant change.
I've seen enough cars that were fine in the winter and start suddenly overheating when it gets hot outside...without exception they needed a new radiator. At 11 years old if you haven't ever replaced the coolant, your cooling system is sludged up.
Originally Posted By: Brad_C
According to the images I've found of a 2004 Honda Civic Thermostat it has the stopper on the back of it that blocks off the recirculation passage in the head as the thermostat opens.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
+1 My thought is head gasket. Are the fans cycling normally?
According to the images I've found of a 2004 Honda Civic Thermostat it has the stopper on the back of it that blocks off the recirculation passage in the head as the thermostat opens.
The concept is simple, while the thermostat is closed the water pump circulates coolant through the head and block and it is sourced from a hole in the head just behind the thermostat. This prevents hotspots, helps warmup and ensures your heater works as quickly as possible. As the thermostat opens, it also places a stopper (the little disc on the end of the thermostat) across that hole to *prevent* further recirculation, ensuring that the coolant flows through the radiator.
When you remove the thermostat, you no longer have the stopper required to prevent the short circuiting, and therefore a not insignificant percentage of the coolant recycles rather than passing through the radiator, causing overheating.
+1 My thought is head gasket. Are the fans cycling normally?
Last edited:
- Status
Similar threads
