An exhaust gas turbocharger includes a housing having an exhaust gas inlet and an exhaust gas outlet. The exhaust gas turbocharger also has a turbine wheel rotatably mounted in the housing. The exhaust gas turbocharger includes a shut-off device that can adopt both an open and a closed state, a fluid connection existing in the open state and allowing exhaust gas which enters via the exhaust gas inlet to flow to the exhaust gas outlet, bypassing the turbine wheel. When the housing is supplied with compressed air, the exhaust gas turbocharger is at least substantially airtight.