An expansion tank arrangement is for a cooling circuit. The expansion tank arrangement has: an expansion tank having a housing with an internal volume configured to receive a cooling fluid; a fluid connection configured to connect the expansion tank to the cooling circuit for supplying the cooling fluid; and a pneumatic connection configured to connect the expansion tank to a pneumatic supply device for pressurizing the expansion tank with a pneumatic medium using a pneumatic supply line. A valve that is configured to influence the pressurization of the expansion tank is in the pneumatic supply line between the expansion tank and the pneumatic supply device.