Regular cooling system fluid flushes reduce the chance that a very costly repair will be needed and the chance of an unexpected breakdown. Engine coolant (or anti-freeze) changes chemical composition over time. This change results in a very corrosive fluid which can damage engine parts and create scale that blocks coolant passageways. There are "long life" anti-freezes available, but their effectiveness is not proven. There are still some studies that indicate that they too become corrosive and destroy internal engine gaskets. We suggest changing engine coolant every 24 months or 30,000 miles.