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.
You want to make sure you do not put tap water into the cooling system on your vehicle. The cooling system has a leak, which is why you need to refill it periodically.
Look on the ground where you park and note any wet spots. Check all the hoses to and from your radiator for any signs of a leak such as wet fluid or runny looking patches of evaporated fluid (can have many appearances). Check around the radiator itself, and around the reservoir. Look for steam or "white smoke" from the engine bay and exhaust pipe while the car is warm (not when you first start it!!!!) and running. If you don't see any at idle have a buddy pull on the throttle. You can pull the spark plugs out and make sure they all look the same.
If nothing else, you can buy a tool and pressure test the cooling system. Sometimes the system will hold at idle but not on the road. Beyond that it may be time to take your vehicle to a mechanic for diagnosis. Good luck!
You also need to check the coolant tank if it has one, it may have a leak or the connecting hose has a leak, and when the water in the radiator expands, it's lost to the leak.
