1. Park your Volvo S40 on level ground and turn off the engine. Allow the engine to cool down completely.
2. Open the hood of your car and locate the coolant reservoir. It is typically a translucent plastic tank with a black cap.
3. Remove the coolant reservoir cap. Be careful, as the coolant may be hot and under pressure.
4. Check the level of the coolant in the reservoir. It should be between the "MIN" and "MAX" marks.
5. If the coolant level is low, add a 50/50 mixture of antifreeze and water to the reservoir. Use the type of antifreeze specified in your car's owner's manual.
6. Replace the coolant reservoir cap and close the hood of your car.
7. Start the engine and let it run for a few minutes. This will circulate the new coolant throughout the engine.
8. Check the coolant level again after the engine has cooled down. If necessary, add more coolant to the reservoir.
_It is recommended that you change the antifreeze in your Volvo S40 every 2 years or 30,000 miles._
