Exhaust Manifold

Manifolds are cast iron or welded steel. On many modern engines the manifold is built into the cylinder head or combined with the turbo. Oxygen sensors are often fitted near it. Turbocharged engines often use manifolds made of special heat-resistant steel because temperatures can be very high.

Exhaust gas leaves each port into the manifold and flows into the downpipe, catalytic converter or turbine.

A cracked manifold or leaking gasket causes ticking noises, especially when cold, and can affect oxygen sensor readings. Broken manifold studs are a common cause of leaks on older engines.