Service includes draining the system of old, tired, dirty coolant, and refilling it with the correct, new coolant for your car or truck. Also called "radiator fluid exchange" or "coolant flush".
What it is: Engines create so much heat that they would melt into a solid block of metal if not cooled down. A cooling system, filled with liquid radiator coolant, moves the heat away from the engine to the air. The constant high heat breaks coolant down over time. Acids form that can damage the cooling system.
Benefit: Coolant exchange makes sure your coolant can do its job keeping the engine cool. It also gets rid of any acid that builds up in the coolant, keeps the engine from locking up or boiling over, and helps prevent corrosion. Fresh coolant has chemicals to help slow any rust or corrosion, so your radiator will live longer, too.