Download Draining 1. Bring the engine to normal operating temperature and turn the engine off. With the cooling system under pressure, inspect cooling system hoses and clamped hose connections for leaks, excessive deterioration or contact wear. Inspect radiator installation retention. Note any discrepancies and proceed. 2. WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system.