what does a expansion tank do in a car
Expansion Tanks. The expansion tank is a vital part of your car's cooling system and acts as an overflow reservoir catching the water/coolant mix that is forced from your radiator as it heats and builds pressure in the system. cooling systems would explode under pressure or the coolant would be forced from the overflow tube on the radiator and leak onto the road. If your find yourself having to replace coolant too regularly then check your expansion tank and the rest of your system for leaks.