The Radiator Coolant Overflow Reservoir Expansion Tank is an important part of your Mazda3's coolant recovery system. This system ensures that the coolant is kept within the system as it will collect the expanding coolant heated by the engine, and once it is cooled down, it will recycle the coolant back into the system. It's important to have a properly functioning cap to prevent debris and other contaminants from getting in.
Details
Special Notes