Your engine needs a proper mix of fuel and air to keep the combustion process running. For this reason, your vehicle is equipped with an intake manifold, which delivers filtered air or a fuel/air mixture into the cylinders.
The intake manifold is secured to the cylinder head with several bolts, and is sealed with a gasket. Depending on the engine design, your intake manifold may also contain passages for proper coolant and/or oil circulation to prevent its overheating. In some cases, it can also house fuel injections that spray fuel into the intake manifold to make a proper fuel/air mixture.
Your intake manifold is a major air induction system component. It is responsible for an air supply into the engine, which is why its failure or incorrect operation may lead to a number of problems. Here are the most common of them:
If you notice coolant leaks on the ground under your engine, this can be a sign of a leaking intake manifold. You should inspect the intake manifold and the gasket for damage and leaks. If a leak is detected, check the color of the leaking fluid with the coolant in the coolant expansion tank. It is also a good idea to check the coolant level and top it up if necessary.
Rough idling or stalling
A cracked intake manifold or a worn-out gasket can allow the outside air to enter the engine. This will cause the engine to run too lean, resulting in erratic idling and stalling at low speeds.
Poor engine performance
A leaking intake manifold will affect an air/fuel mixture. As a result, you can experience a number of engine performance problems, including poor acceleration, rough idling, backfiring and misfiring.
Increased fuel consumption
Your engine control unit will try to compensate for extra air that enters into the system due to an air leak. It will force more fuel into the engine, significantly increasing your fuel consumption.
Abnormal noises during idling
If you notice any kind of abnormal noises coming from the intake manifold, including whistling, gulping, sucking or hissing, you possibly have a leaking manifold. You can check the source of the noise if you open the hood and let the engine idle.
Illuminated check engine light
Engine problems that appear due to a faulty or malfunctioning intake manifold can make the engine control unit turn on the check engine light on your dashboard.
A leaking air intake manifold can cause a low level of coolant in the cooling system. Due to a lack of coolant, the engine can run hotter or get overheated. If this is the case, your temperature gauge should provide high readings, and the temperature warning light and the check engine light should also come on.
Driving a vehicle with a bad air intake manifold is not recommended for several reasons. Your engine can get overheated and even damaged, which may lead to a road accident if it fails or stalls while you’re driving.
Air intake manifold troubleshooting and replacement
Depending on your vehicle, you may have a different type of intake manifolds. It can be made of steel or plastic and come with or without coolant and/or oil passages. Regardless of its type, a proper diagnosis done by a professional is required before replacing or working on your exhaust manifold.
In most cases, you may just need to replace the gasket or tighten a loose bolt, however, sometimes, a complete air intake manifold replacement is required. Whichever the problem, we recommend you to hire a mechanic to fix it. He or she will need to remove the manifold, replace a faulty part and assemble everything back in the reverse order. This involves lots of labor and proper understanding of air intake system operation.