The water in my radiator keeps depleting I've checked for leaks but I can't seem to find any. Every morning when I check the radiator I have to fill it up for about a litre. Yesterday I didn't use the car much so I topped the radiator water at night to see if it stays the same in the morning. And no, it didn't. I still had to top it up half a litre of water even though the car was idle the entire night. I still couldn't see any leak. What could be the problem?
I drive a 2001 Honda Civic.