As a general rule of thumb, you should get a coolant flush every 30,000 miles or three to five years, whichever comes first. Your car’s owner’s manual should also outline a more specific interval depending on the manufacturer.
When should I flush my radiator?
Generally speaking, you should flush your radiator once every five years or every 100,000 miles that you drive.
What happens if you dont flush coolant?
The coolant can become more acidic over time and lose its rust-inhibiting properties, causing corrosion. Corrosion can damage the radiator, water pump, thermostat, radiator cap, hoses and other parts of the cooling system, as well as to the vehicle heater system. And that can cause a car engine to overheat.