|Quoting Luisde8cd (Thread starter):
A simple question... what's the recommended mileage-interval in which you have to drain your engine coolant and replace it with a fresh one? Also, what can happen if you don't change your coolant? Overheating perhaps?
Most modern cars do not require coolant flushes for 100,000 miles (160,000 km) if they use DEX-COOL coolant (red). If you use standard (green or others) coolant, it is a good idea to flush every 15,000 miles (24,000 km) or so.
If you don't change your coolant, some very expensive things can happen. As coolant ages, the corrosion inhibitors break down. As they break down, a sludge starts to form in the low points of your cooling system, consisting of corroded metal. This can play havoc with thermostats, water pumps and radiators, blocking flow or getting into moving parts. If this happens, you are likely to either overheat or blow a head gasket.
[Edited 2007-04-23 21:22:33]