This toothed drive belt ensures the engine valves open and close at the exact right moment in relation to the pistons. It is housed at the front of the engine under a protective cover and requires replacement at strict mileage intervals. If it snaps on an interference engine, the pistons will smash into the open valves, causing catastrophic internal damage.
We need to pull the water pump while we're in there doing the timing belt, since it runs off the same tensioner.
Always replace the tensioners, idler pulleys, and water pump when doing a timing belt job, as the labor to access them is the most expensive part.
Also heard as
- cam belt
Do not mix it up with
- Timing chain: A timing belt is made of rubber and requires periodic replacement, whereas a timing chain is metal and designed to last the life of the engine.
Related terms
Timing chain
A heavy-duty metal roller chain that synchronizes the engine crankshaft to the camshafts.
Cylinder head
This cast metal component bolts to the top of the engine block to seal the combustion chambers.
Overhead cam
A valvetrain layout where the camshaft is located in the cylinder head above the combustion chamber.
Crankwalk
Excessive axial play in an engine crankshaft that allows it to shift back and forth.