An integral part of the cooling system for your vehicle, the thermostat is an inexpensive item which, if it fails, could cause catastrophic engine failure. Often overlooked, it’s a good idea to change it when you change your coolant. Given hoses outlast thermostats, if your hoses need changing, your thermostat probably does too. While there are many variables, some say the average life of a thermostat is 10 years. However, not worth leaving to chance.