On older vehicles equipped with standard coolant/antifreeze, the cooling system should be drained and refilled with new coolant at least every 30,000 miles or 24 months. If desired, a flush system designed specifically for aluminum cooling components should be used. Follow the instructions on the package.
On vehicles with G11 and G12 coolant/antifreeze, (blue-green and red, respectively). Both G11 and G12 coolant is considered a 'lifetime' coolant, the manufacturer does not recommend any special cooling system flushing or replacement unless the system has been drained, contaminated, or a cylinder head gasket or cylinder head has been replaced.
If the system is contaminated, drain the coolant and install water. Run the engine until it is hot and drain the water. Install the proper mixture of the recommended coolant.