The part of an engine which carries exhaust gas from the head to the exhaust pipes and silencer(s). It is easy to recognize as the part of the engine which will be rusty within the first few thousand miles. When the engine is running it will be at a temperature above 400 Deg F. and should not be touched with bare skin.

As with the rest of the exhaust system, the studs or bolts which mount at either end of the manifold are prone to corrosion and therefor are notoriously difficult to dismantle without creating stripped threads. Assembly of this part of the engine should always include use of anti seize compound.

Some people use this part of the engine in cooking food while driving.