PCF000033LR - Tank - Overloop radiator

The expansion tank is the coolant overflow and reservoir in the engine cooling system. It takes up the change in coolant volume as the engine heats and cools, holds system pressure through its cap, and gives the fill and level-check point for the circuit.

The expansion tank sits in the cooling circuit of the Range Rover L322 with the 3.0-litre BMW M57 diesel. It's a genuine Land Rover part mounted in the engine bay, feeding and pressurising the coolant system.

Expansion tanks fail because the moulded plastic and seams grow brittle with heat and pressure cycling, and the cap can lose its seal. On the L322 TD6 that typically shows as coolant loss, a low-level warning or overheating. Replace it once it weeps or cracks.