The intake manifold is a series of tubes that disperse air equally to each of the cylinders entering the engine so that the right amount of air can be combined with the right amount of gas. Many internal combustion engines operate on a four-stroke cycle, and air from the intake manifold is drawn into each cylinder through a valve or piston during the first stroke, called the intake stroke.
The oxygen needed by the engine of a car originates from the ambient air. Oxygen accounts for about 20 percent of the air we breathe, and it is the function of the air intake system to 'take in' and guide air through the intake manifold and into the combustion chamber to ensure proper internal combustion.
These factors can disturb the intake manifold's proper functioning. The Engine Light often turns on when there is a problem in the intake manifold.
Carbon buildup is caused by oil flowing through usual intake valve seals, and by gas blowing from usual crankcase as well. Shell, Exxon, Mobil, as well as the other refiners, mix gasoline with high levels of detergent to clean injectors of fuel and intake valves.
The intake has a coolant cross over tubes which guides the coolant from head to head of one cylinder. When you have a crack in the intake manifold and the coolant leaks then as the engine is running and the cooling system is hot and pressurized the coolant may leak at a rapid rate allowing the engine to heat up and the possibility of damage to the engine will arise.