This core plug (also known as a freeze plug or expansion plug) seals one of the machined openings in the engine block left over from the casting process. On TD5 and other engines in this range, failed or corroded core plugs result in coolant loss directly from the block, which can rapidly lead to overheating if undetected. Replacement is necessary when plugs show signs of rust, weeping, or physical displacement. Key Features Designed to seal engine block casting apertures against coolant leakage Correct fit for the specified bore diameter in applicable Land Rover engines Meets OEM replacement specification for the listed engine families Check all remaining core plugs when replacing one, as corrosion typically affects multiple plugs simultaneously Vehicle Fitment Fits Defender (1986–2006) TD5, Discovery 1 (1989–1998) 2.0 Petrol, Discovery 2 (1998–2004) TD5, Freelander 1 2.0 Rover Diesel, and Range Rover Classic 3.9 V8 Petrol (Inlet Manifold to XA410482). Not sure about fitment? Feel free to get in touch at [email protected]