Park the car on a level surface and turn off the engine
Let the engine cool completely
Open the hood
Locate the coolant reservoir
Check the coolant level against the MIN and MAX marks
If needed, slowly remove the reservoir cap
Add the correct coolant type recommended for your car
Pour coolant into the reservoir until it reaches the MAX mark
Reinstall the cap securely
Check for leaks around the reservoir and hoses
Close the hood
Start the engine and monitor the temperature gauge
Recheck the coolant level after the engine cools again