I know that a lot of people have suggested bleeding the system with a bleeder valve but there are some honda engines without one. My car was overheating all of a sudden this week. I pulled the radiator cap while the engine was cool and let the engine run watching the coolant. I ended up having air in the system. Just let the car run with the cap off until there are no more bubbles coming up. It might take a while. You may even have to add coolant at some point. I hope that helps.