by Alexis Writing
luxury car – toy car model image by alma_sacra from Fotolia.com
The exhaust manifold is an important component of the exhaust system. Engine gases are expelled through the exhaust manifold into the tailpipes and out of the vehicle. The manifold is connected to many small tubes, which collect the exhaust gases from the exhaust stroke through the engine pistons. The vehicle’s head gaskets ensure that the exhaust is transferred to the manifold so that it does not enter other areas of the combustion system. Sometimes, however, the exhaust manifold can develop leaks.
Because the exhaust manifold is connected to other parts of the exhaust system, many of the symptoms of a [exhaust manifold leak](https://itstillruns.com/exhaust-manifold-leak-5040401.html) can also be symptoms of problems with other parts of this system. However, a strong smell of gas in the emissions is a major symptom of an exhaust manifold leak. This occurs because not all gas passes properly through the exhaust system as a result of the manifold leak, resulting in emissions with a stronger gas odor and higher concentration of soot.
Emissions test failure
If your vehicle fails an emissions test, this is another major symptom of an exhaust manifold leak. A manifold leak causes oxygen to enter the exhaust stream, resulting in improper fuel mixing and higher emissions. When your car fails the emissions test, the mechanic must determine whether this failure is the cause of an exhaust manifold leak or the result of other exhaust system problems.
Unusual engine sound
An unusual engine sound is another symptom of an exhaust manifold leak. Most of the time, this takes the form of a strange knocking near the exhaust pipe. This can be a difficult symptom to detect because it can be difficult to hear the tapping over regular car noises, especially while driving.