The expansion tank of a Rover 25 is located on the right hand side of the engine bay, looking from the front of the car, and is a translucent black plastic container with a black lid. To open the lid, just turn it anti-clockwise. When the car is cold, the level should be between the 'MIN' and 'MAX' marks on the side of the tank.
To top up the coolant, simply take the cap off the expansion tank and add the coolant to the tank until it reaches the required level. If the level is too high, the coolant will expand when the engine heats up and may overflow from the tank. If the level is too low, the engine may not run efficiently and could overheat.
