LR017427 - Dop van overloopreservoir

The Overflow Container Cap seals the cooling system expansion, or overflow, reservoir and maintains system pressure. It lets coolant expand and recover as engine temperature changes while keeping the cooling system sealed. A cap that holds pressure correctly helps the engine run at its designed temperature.

The Overflow Container Cap fits on top of the coolant expansion (overflow) reservoir in the engine bay. It's the cap you take off to check or top up coolant. It seals that tank and holds the cooling system's operating pressure across the models it fits.

This cap fits a wide range including Discovery 4 and 5, New Defender (L663), Range Rover L322 and L405, Range Rover Sport L320 and L494, and Range Rover Velar. It spans several diesel and petrol engines, so it's shared across many cooling systems. Check your reservoir matches before ordering.

A failed Overflow Container Cap typically stops holding pressure, which can cause coolant loss, overheating, or the cap venting early. Signs include a persistent low coolant level or steam from the reservoir. Replacing a worn or cracked cap restores the seal and correct pressure.