The invention relates to a masking system for masking a cylinder bore (2) of a combustion engine (3) during a thermal coating procedure including a masking body (4) which can be placed during the thermal coating of a first cylinder (5) of the combustion engine (3) in the cylinder bore (2) of a second cylinder (7) to cover a cylinder wall (6) of the second cylinder (7). In this arrangement the masking body (4) is designed in such a way that a flow gap (10) of predeterminable breadth can be set between the masking body (4) and the cylinder wall (6) of the second cylinder (7) for the production of a flow (8) of a fluid (9).