Intake Manifold Leak Symptoms

Updated February 21, 2017

The intake manifold helps the engine reduce its load. The intake manifold is a set of pipes that supply the right mixture of fuel and air as it passes from the carburettor to the engine. This is a critical part of the combustion process that helps ensure the engine receives optimal fuel to deliver at optimum levels. An improper distribution of air and fuel mixture results in improper horsepower delivered to the engine. There are several symptoms associated with an intake manifold leak.

Drop in Output

When there is a leak in the intake manifold, this results in a drop in the engine's output. When the leak occurs, fuel is not delivered in the right proportion to the engine. This means a drop in power. If you have difficulty accelerating or maintaining speed, this could be a sign of a leak.

Oil Dripping

When there is a leak in the intake manifold, fuel has no place to go other than to the base of the vehicle. This results in a small oil pool below the car. When the leak is large enough, even a few minutes of idling can make this mini oil lake appear. A leak in other pipes can also result in gas spills, so you need to make sure the leak is actually caused by the intake manifold. To check this, verify if the fuel on the ground also has water or steam in it. If it does, the drip is probably caused by an intake manifold leak.


Noisy idling is another sign of a leaky intake manifold, especially if the leak is located in the intake manifold gasket. This type of leak can also result in difficulty turning the engine off. A leak in the intake manifold also means air is released into the open, which the engine can absorb. This results in a slurp or lisping sound in the engine.

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Alexis Writing has many years of freelance writing experience. She has written for a variety of online destinations, including She holds a Bachelor of Arts in communication from the University of Rochester.