Antifreeze is added to a 2005 Honda Civic at the coolant overflow tank. Antifreeze is added at a ratio of 50/50 with water for optimal cooling.
In the radiator.
Prestone
I think its blue
The amount of anti-freeze that you put in your Honda Civic is dependent upon the colon level in your cooling system. The manufacturer recommends that you keep a minimum of 50 percent antifreeze in the cooling system.
Your best bet is to call the dealership for a recommendation.
It was a bad answered that talked about changing the antifreeze -- not the airconditioning freon.
You have air trapped in the cooling system that needs purged out of the system.
There is not really a way to tell you how antifreeze got on the Honda Civic ex. You will have to be more specific on where you found it on the back the car. Have the cooling system pressure tested. That may make the leak more obvious.
Blown head gasket.
When changing the antifreeze first drain the old fluid by disconnecting the lower radiator hose. Plug the hose in and add coolant to the radiator. Check for air in the system, bleed if necessary.
Diagnostic port is either under steering wheel or near the engine antifreeze line (under the hood).