For the engine to run, the intake manifold has to be properly sealed to the cylinder head. The intake manifold gasket does this. It may be made of rubber or paper.
How does the intake manifold gasket work?
The intake manifold is a distribution system for air, and sometimes fuel. As the throttle body opens, the engine intake stroke sucks in air through the intake manifold. Cars that don't use direct injection will distribute fuel this way as well, but this system is becoming less common.
Negative pressure, or a vacuum, builds up inside the intake manifold, and the manifold gasket is used to prevent any unwanted air from entering the system.
An intake manifold gasket can be the source of a vacuum leak and/or engine coolant leak.
An intake gasket with a vacuum leak will often have a rough idle and engine misfires. This may turn on the Check Engine Light and set misfire and/or fuel mixture "out of range" trouble codes.
Some intake manifolds are made of plastic. They can become pitted and may need to be replaced along with the intake gaskets.
What are the symptoms related to a bad intake manifold gasket?
Problems with the intake manifold gasket can create the following symptoms:
Can I drive with a intake manifold gasket problem?
A problem with the intake manifold gasket can make life hard on the engine. It's often best to have the car towed to a repair shop in this situation to avoid further damage.
How often do intake manifold gaskets need to be replaced?
There's no set schedule to replace the intake manifold gasket. It's designed to last the life of the vehicle, but often it will be replaced when doing related engine repairs in order to prevent problems with it down the road.
How are intake manifold gasket issues diagnosed?
If the above symptoms are present, the technician can test the intake manifold gasket by connecting a smoke machine to the manifold with the engine off. The pressure will push smoke out of any leaking parts, including the intake gasket.
How is a intake manifold gasket replaced?
Typically, the intake manifold will have to be removed to replace the gasket. This can be a large job that may involve draining the engine of coolant and oil and removing many engine components.
Many vehicles, however, are designed with plastic intake manifolds that do not have oil passages or coolant passages, and are much faster and more cost effective to remove and reinstall.
BMW 645Ci Intake Manifold Gasket Replacement Cost by Year
The average cost for a BMW 645Ci Intake Manifold Gasket Replacement is between $643 and $842 but can vary from car to car.
