Timing belts and kits

How you know it is this

• The service interval has come up — this is a scheduled item, not a fault
• Cracking or glazing visible on the belt
• Oil contamination on the belt from a leaking seal

Worth knowing before you buy

• Unlike a chain, a belt is replaced on a schedule. It gives no warning before it breaks, and when it breaks the engine is usually destroyed.
• Always with the tensioner, idlers and normally the water pump, because the pump is behind the belt and its labour is already paid for.
• Most Mercedes engines use a chain. If you are not sure which your car has, the engine code settles it.

Rest of the timing

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