The radiator drain plug for a 2001 Astra is located at the bottom of the radiator, on the passenger side of the car. It is a plastic plug with a 17mm head. To drain the radiator, place a drain pan under the plug and then loosen the plug using a 17mm wrench. Be careful not to drop the plug into the pan. Once the plug is loosened, allow the radiator to drain completely. Once the radiator is drained, replace the plug and tighten it securely.
