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.
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.
The engine size of the Honda Civic is 1.8 litres.
0.75Amps
The 2011 Honda Civic has an inline 4 engine.
The 2006 Honda Civic has an inline 4 engine.
The 2005 Honda Civic has an inline 4 engine.
The 2004 Honda Civic has an inline 4 engine.
The 2014 Honda Civic has an inline 4 engine.
The 2001 Honda Civic has an inline 4 engine.
The 2008 Honda Civic has an inline 4 engine.
The 2007 Honda Civic has an inline 4 engine.