A clear plastic container is what several cooling systems are making use of. This container is what we've known as the expansion tank, which I connected to the overflow tube from the radiator. It provides extra storage space for the coolant when it expands. The coolant inside the engine expands whenever it absorbs heat from the engine. If not for your Saab expansion tank, the coolant would then just flow out of the overflow tube and be lost from the cooling system onto the street. With the aid of a vacuum, the coolant heading to the overflow tube is sucked back and directed into the tank. And because a cooling system is a closed system, the coolant is able to flow only between the system and the expansion tank every time it expands and contracts. As a result, no coolant is lost. When time comes that your Saab expansion tank begins to fail, you have to inspect it right away. If the inspection tells you that it's time to find a quality Saab expansion tank replacement, never have second thoughts. Besides, you deserve to drive a vehicle that's equipped only with the finest products. In that way also, you are able to spare yourself from more replacement and repair costs because the other possible damages were prevented from occurring. Aside from the aforementioned benefits your vehicle gets from an expansion tank, it also able to remove the air bubbles from the coolant. With that, the coolant is more efficient in heat absorption. Moreover, it is always best to have a good working condition expansion tank so as to maintain the level of coolant needed for efficient engine cooling. Should you need to dump that damaged expansion tank, you can always find a quality Saab expansion tank replacement when you do shop here at our online store.