These drain taps have been plagued with leakage problems. To prevent any leakage and preserve the original appearance, we modified the design to incorporate an internal threaded plug. The included plug is threaded into the drain tap with a sealing washer prior to installation in the radiator or engine block. When installed, the plug will reliably seal off the tap, preventing any leaks. And, as you have just realized, the plug will prevent any coolant from draining through the tap, no matter what you do with the handle. As an alternative, you can purchase a simple and less expensive plug (part #36495).