How to Do a Radiator Flush – Step-by-Step Guide
Why a Radiator Flush is Important
A radiator flush removes old coolant, rust, scale, and debris from your cooling system. This helps prevent overheating, improves heater performance, and extends the life of your water pump, thermostat, and radiator.
Step-by-Step Radiator Flush Instructions
1. Prepare Your Vehicle
-
Park on a level surface and let the engine cool completely.
-
Wear safety gear to protect your skin and eyes from hot coolant.
2. Drain the Old Coolant
-
Locate the radiator drain plug at the bottom of the radiator.
-
Place the drain pan underneath and open the plug to let old coolant flow out.
-
Dispose of used coolant at a recycling center—never pour it down the drain.
3. Add Radiator Flush Solution
-
Close the drain plug.
-
Pour in radiator flush solution or distilled water using a funnel.
-
Fill up to the manufacturer’s recommended level.
4. Run the Engine
-
Turn the heater on high.
-
Start the engine and let it run for 10–15 minutes so the flush solution circulates through the entire cooling system.
5. Drain Again
-
Turn off the engine and let it cool.
-
Open the drain plug and remove the flush solution along with loosened debris and rust.
6. Refill with Fresh Coolant
-
Close the drain plug securely.
-
Fill the radiator with the correct type of coolant (refer to your owner’s manual or coolant compatibility chart).
-
Top off the coolant reservoir.
7. Bleed Air from the System
-
Start the engine with the radiator cap off (if safe per manufacturer’s instructions).
-
Allow trapped air bubbles to escape.
-
Replace the cap once coolant level stabilizes.
Pro Tip: A radiator flush is an excellent time to inspect your thermostat, water pump, and radiator hoses for wear.
How Often Should You Flush a Radiator?
-
Traditional green coolant: Every 2 years or 30,000 miles.
-
Extended-life coolant (OAT/HOAT): Every 5 years or 100,000 miles.