About 1 year ago i was traveling home and my 99 Honda Civic started over heating (getting close to red). I was no where near home and it was 1 AM in the morning. I pulled over and checked my coolant. All of my coolant went into my reserve tank so i blasted the heat in the car to cool it down then drove as slow as possible home. The problem just kind of went away the next day. So yesterday (a year later) i was driving to and from the san diego airport (about 65 miles round trip) and my car started to do the same thing except when i went to turn on the heat in my car to cool it down, no heat came out. Only cold outside air. Im not sure where to start as its not throwing a check engine light and it only happens when i travel long distance.

- All the coolant goes into the reserve tank
- No heat from the heater

Any advice would be great.

Thanks,
Ryan

 

Sounds like a bad thermostat but if all your coolant is going into your overflow bottle could also be a bad radiator cap. Both of which are inexpensive to replace. The thermostat is just a bit messy to change out (drain all coolant), remove the thermostat replace with new one.
But if your car is overheating with the heat on in your car? Is the radiator fan coming on? How old is your radiator? Is it filthy? How old is your coolant?

 

Thanks for the response.

Yes my car is over heating with the heat on. (sometimes no heat comes out though) The radiator fan is coming on and my radiator is almost 2 years old. Its not filthy. My coolant is the same age as my radiator (2 years).

 

Also could be a bad heater core (maybe clogged, maybe hose to the core is clogged).

Hrm also could be a bubble in the system too. Who replaced the radiator and filled it? Might have to raise the front by parking it on some wood planks. Make sure the car is cool and pop the radiator cap off. Turn the car on and let it warm up. Let it run for about 10-15 minutes making sure the radiator fan comes on, and turn on the heat to hot. If bubbles come up the neck of the radiator you might have air bubbles in the system. So as the coolant drops add more.

 

Thanks ill try that!

 

Got the same issues here
I replaced the radiator and thermostat flushed it out had a pressure test done and it held normal pressure. Checked oil and plugs to see if head was bad all is good, the fan comes on when it suppose to. I have gone thur the whole cooling system. If I run the heater temp will drop to normal. I even used K&W sealer to seal any internal problems, still no luck. HELP!!!!!!
2 years ago