You'll likely need to get under the car to locate it. Look carefully at the bottom of the radiator for a small, typically brass or plastic, plug. It may have a square or hexagonal head suitable for a wrench or socket.
Before attempting to drain the radiator:
* Consult your owner's manual: This is the best source for the exact location and draining procedure specific to your vehicle.
* Let the engine cool completely: Hot coolant is under pressure and can cause serious burns.
If you can't find it after a careful search, it's best to consult a mechanic or a repair manual specific to your 2003 Buick Regal.
