I have owned this car only a couple months.Temperature gauge was fluctuating. Heater was intermittent. Assumed it was thermostat and replaced it. Refilled with Honda coolant. For 2 days it was normal. On the 3rd day it overheated and pushed excess coolant into the reservoir and it overflowed. After cooling, I took off radiator cap and radiator was almost empty. Apparently excess air was getting into the cooling system and pushing coolant into reservoir. The exhaust is clean, no moisture on the oil cap, engine runs smoothly. I am not losing coolant. Each day before I drive it to work, I transfer excess coolant back to the radiator from the reservoir and it runs fine and heater works for the most part. This transfer process is good for 60 miles without overheating. Could there be a blockage in the cooling system? Any ideas? Advice?

 

New radiator cap?

Did you bleed the system?

 

I did not get a new radiator cap. It does hold pressure and it looks fairly new. After the engine has cooled down, I open the cap I can hear pressure being released. And then I do my fluid transfer. Yes, I did bleed the system for a good half hour.