The ERR4686B is a radiator drain plug designed for plastic radiators fitted to Land Rover Defender models equipped with the Tdi engine, up to chassis number TA976035. It seals the drain port at the base of the radiator, preventing coolant loss during normal operation. A failed or cross-threaded drain plug can result in persistent coolant leaks, leading to overheating and potential engine damage if left unaddressed. Key Features Designed specifically for plastic-tank radiators fitted to Tdi-engined Defenders up to chassis TA976035 Direct OEM-specification replacement - ensures correct thread engagement and sealing on the plastic radiator body Should be inspected whenever the cooling system is drained; plastic threads on the radiator are susceptible to damage from overtightening Replace the sealing washer or O-ring alongside this plug if signs of coolant weeping are present around the drain port Vehicle Fitment Fits Defender (1986–2006) with Tdi engine and plastic radiator up to chassis TA976035, and also applies to 300Tdi variants of the Defender, Discovery 1 (1989–1998), and Range Rover Classic. Not sure about fitment? Feel free to get in touch at [email protected]
