Abstract: A motor vehicle coolant heat exchanger having a modifiable covering system includes a support, a winding shaft mounted rotatably around a winding axis, a rotational drive, a roller-blind web, at least one pulling means winding body connected to the winding shaft to rotate together, and a pulling means. The roller-blind web is windable onto and unwindable from the winding shaft along a winding trajectory, which comprises a pulling crosspiece at its longitudinal end region located remotely from the winding shaft. The pulling means is unwindable from and windable onto the pulling means winding body parallel to the winding trajectory, which is connected at its longitudinal end remote from the pulling means winding body to the pulling crosspiece. The pulling means is guided around a deflection roller in such a way that its longitudinal end connected to the pulling crosspiece moves away from the winding shaft while it is being wound on.