To perform his duties during his temporary-absence or disability the City Manager, by letter filed with the City Clerk, may appoint a qualified administrative officer of the City to be Acting City Manager. If the City Manager fails to make such designation, or if the Council suspends the City Manager, or if there is a vacancy in the office of the City Manager, the Council may appoint an Acting City Manager to serve until the City Manager returns, or until his disability or suspension ceases, or until it appoints another City Manager. The Council must appoint a new City Manager within six (6) months after the office of City Manager becomes vacant. The Council may suspend or remove an Acting City Manager with or without cause at any time by a vote of a majority of all its members.