Jaguar, Land Rover, genuine Tensioner No: LR004786

LR004786 is a timing belt tensioner for the Cologne 4.0 V6 EFI engine. Fitted at the front timing gear, the tensioner applies and regulates tension to the timing belt to keep camshaft and crankshaft positions synchronised and to prevent belt slip or tooth skipping. It compensates for belt stretch and material wear, helping to reduce belt vibration and noise while maintaining steady timing during engine speed changes. During timing belt replacement the tensioner is commonly replaced to restore correct pre-load; inspect the unit for smooth movement and for absence of seizure or noisy operation to identify wear before it affects engine timing.