Radiator coolant should be replaced every two years and use distilled water when toping off, it does deteriorate with time and heat, radiators will calsify and plug, if you live near salt water the radiarors will corrode to the point that you can run your finger down a row and have nothing but flakes, all coolant hoses should be replaced from 4 to 6 years dependig on where you live and type of commuting, hoses tend to rot from inside out and pin holes appear where they flex as the engine moves or rocks on the motor mounts when toque is applied.
navegator