Does this plug normally get opened when changing the coolant. Does any one know how much coolant is in the engine block? I drained about 1 gallon of coolant from the radiator drain plug.Honda accord engine block coolant drain plug?Leave it alone, if your coolant was clean just close radiator drain and refill according to specs, if coolant was dirty then flush system and refill.Honda accord engine block coolant drain plug?The plugs on the block are not designed to ever come out!!!!!!!! You screwed up big time. Most likely you will need to replace that frost plug ( have a professional do it). To drain the coolant just take off the lower radiator hose and let it drain out to flush it out then take a garden hose and run it in through the upper intake on the engine or through the radiator.
After you think you are done have you coolant system pressure tested and tell them that you hacked away at the frost plugs and to be checked for leaks.
Before you try any repairs on your car make sure you read up on it and know what you are doing to prevent damaging something you know nothing about!