Timing chain tensioners

How you know it is this

• A rattle on start-up that disappears once oil pressure builds
• A rattle that has started to last longer than it used to
• A timing fault code with a chain that measures within tolerance

Worth knowing before you buy

• A tensioner bleeds down when the engine stops. A short rattle on a cold start is normal; a long one is not.
• Cheap relative to the chain, and always fitted with one.
• A tensioner that has failed because of poor oil pressure will fail again unless the oil problem is found first.

Rest of the timing

• Timing chains
• Timing chain guides and rails
• Timing belts and kits
• Camshaft adjusters (phase variators)
• Camshaft adjuster magnets / solenoids
• Timing covers and gaskets