Before pulling out the radiator from Chevy Blazer and GMC Jimmy, start with disconnecting the negative end of the battery cable and emptying the cooling system. Start by taking off the air intake duct and upper fan grill. When the vehicle has an automatic transmission or an engine oil cooler installed, carefully take off these cooler lines from the radiator and plug their ends to keep them from leaking. Disconnect the upper and lower radiator hoses. Twist out the lower fan shroud by manually pushing down on two small plastic clips. Finally, pull the radiator straight up and out. First, replace any broken hose clamps and radiator hoses before you reverse-install the radiator, step-by-step. With newer models, put fresh spring clamps on oil cooler connections and make sure they push down tight. After installing the system, put the correct antifreeze mix inside and check the transmission fluid level when it's automatic. First, remove the PCM at the top of the coolant reservoir, then disconnect the overflow hose and mounting nuts so you can take out the reservoir. Be sure to clean the reservoir from old parts, so no dirt affects the system when you put it back.