Exhaust Manifold : The part of the engine that connects the exhaust system to the cylinder head is called the exhaust manifold. An exhaust manifold is made of steel or cast iron. It holds an extreme amount of heat as the fresh exhaust is released from the engine at high temperatures. The exhaust manifold is a very durable part that can handle the extreme heat produced by the engine.
Some exhaust manifolds contain a pre-cat. A pre-cat is a catalyst converter that helps reduce emissions on most vehicles. Most of these types of manifolds have to be replaced as an assembly since the pre-cat is built inside and not replaceable.
Other types of exhaust manifold problems may be rusted exhaust studs or bolts, broken exhaust studs or bolts, or cracking of the manifold. When there are cracks, the exhaust manifold must be replaced. If bolts or studs are rusted or broken, usually these problems can be repaired on or off the car, truck, van or suv.