Drain Cock Replacement: Notes
WARNING: This page is about a different car, the 2003 Chevrolet SSR. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.