On a fuel injected car...
... unscrew the plug of the expansion tank.
Unfasten the rubber fastening strap.
Drain the coolant into a container below.
We loosen the clamp with pliers...
... and, having disconnected the hose from the tank pipe,...
... remove the expansion tank.
On a car with a carburetor engine to remove the tank...
...the key «on 10» Loosen the expansion tank clamp nut.
Install the tank in reverse order.