What Is An Exhaust Manifold
The exhaust manifold is the part of your car connecting the engine to the exhaust system. It’s responsible for collecting all the exhaust and funneling it into the catalytic converter and then onto the muffler and tailpipe. This manifold is generally made from a solid piece of metal for durability, but it’s not impervious to damage. Watch out for these common signs there’s damage to your exhaust manifold and you need timely auto repair.
SIGNS OF AN EXHAUST MANIFOLD LEAKAGE
The following signs could point to a leaking exhaust manifold, so if you notice one or multiple of these symptoms, make an appointment immediately.
1. NOISY ENGINE: One of the clearest indicators of an exhaust manifold leak is strange noises coming from the engine. The engine might sound louder than usual as the gases escape, or you may notice a tapping noise. The ticking or tapping sound happens right after turning on the car. As the exhaust manifold expands, it may close off the leak, and the noise will stop until the next time you start up the car.
2. EXHAUST SMELLS: If you smell exhaust or other gasses in the car, even with the windows rolled up, this may mean the exhaust manifold is leaking. But keep in mind that a leak may also release harmful and odorless carbon monoxide into the car.
3. REDUCED FUEL EFFICIENCY: If you can’t travel as far on a full tank of gas as you could last month, a leak in the exhaust manifold could be to blame. The leak causes oxygen sensors to misread the engine as having a lean mixture; the electronic control unit (ECU) then increases the amount of fuel to compensate.
4. POOR VEHICLE ACCELERATION: Similar to the way an exhaust manifold leak can lead to lower fuel efficiency, it can also make it more difficult for your car to accelerate. It may be a subtle change at first, but the longer you wait to get your car checked out, the worse the acceleration can get. This will make driving not only more difficult but also more dangerous.
5. CHECK ENGINE LIGHT: The leak may also cause the car sensors to trigger the check engine light, so keep an eye out for this helpful symbol that may tell you something is wrong with the exhaust manifold.
6. Visible Damage: Taking a good look at all sides of the manifold after any of the following symptoms may reveal a visible crack in the metal. This crack can be hairline thin or form where the part is pressed against the engine, so don’t rule out a manifold problem just because you can’t spot visible damage.
SOME POTENTIAL CAUSES OF AN EXHAUST MANIFOLD LEAK
When an exhaust manifold leaks, there are a few common reasons, all of which are due to the way the engine heats up when the car is running and then cools down dramatically when the car isn’t in use.
1. Thermal stress: As part of the engine’s exhaust system, exhaust manifolds put up with a lot of heat, literally, every time you drive. Then they cool down considerably when the car isn’t running. All this expanding and contracting can wear down the metal over time, causing it to crack and leak.
2. Worn-out gaskets: To seal the space between the exhaust manifold and the engine block, gaskets help keep gasses from leaking out. The temperature changes also cause the gaskets to wear out over time, and eventually, they will fail and need to be replaced.
3. Broken bolts and studs: Bolts and studs can become brittle due to those extreme temperature changes from hot to cool when the car is running versus not running. If they break, they can cause a leak.
WHEN AND WHY YOU NEED TO REPLACE A LEAKING EXHAUST MANIFOLD
A leaking exhaust manifold needs your attention as soon as possible. Because this part is crucial to moving toxic gasses from the engine to the catalytic converter and ultimately out of the tailpipe as less harmful gasses a leak can be serious trouble. If the gasses leak into the cabin of the car, you and your family will be exposed to carbon monoxide (which can be lethal), as well as volatile organic compounds and other hazardous gasses.
Aside from putting your health at risk, the leak can cause more damage over time to other parts of the car. The exhaust valves can get burned, the leak can damage oxygen sensors, or the problem can cause the catalytic converter to fail prematurely. It may also increase your fuel consumption, meaning you spend more on gas each week.
Some of the points below further list the need for you to consider replacing your car exhaust manifold
1. Reduces Function: As the first component in the exhaust system, the exhaust manifold collects the exhaust fumes released from the engine cylinders and directs them to the catalytic converter. In turbocharged engines, the turbocharger is situated downstream of the exhaust manifold.
The design of the exhaust manifold has a significant influence on the performance and torque characteristics of an engine, as does the design of the connected pipes.
The fact that the individual exhaust tracts are merged into one ensures that pulsations, i.e. fluctuating pressure surges given off by a certain cylinder, do not prevent exhaust fumes being released from another cylinder. What’s more, waves of negative pressure are intended to promote the flow of exhaust fumes out of the cylinders.
Exhaust manifolds are often made of alloyed cast iron, which is able to withstand the high exhaust temperatures. Alternatively, exhaust manifolds made of stainless steel are also used.
2. Safety: Exhaust manifolds are subject to high thermal stress because they are the first component to convey exhaust fumes away from the engine. The significant expansions caused by temperature combine with the associated cyclical tension resulting from repeated heating and cooling to subject the material to fatigue. In turn, this can eventually cause the component to fail. Vibrations cause additional stress. Cracks in components let hot exhaust fumes enter the engine compartment and cause additional, unwanted noise. The materials and designs employed today generally enable the manifold to last for the entire service life of the car.
3. Protection of the environment: To ensure low pollutant emissions, it is important for the catalytic converter to reach its operating temperature quickly. The thermal capacity of the exhaust manifold plays an important part in this. To put things simply: the less mass a manifold has, the more heat is available to the catalytic converter in the start phase.
4. Value retention: Exhaust manifolds should be installed according to the vehicle manufacturer’s specifications. Likewise, when replacing the manifold, new gaskets must be used to ensure that exhaust fumes do not leak from the components. It is also important for the downstream components to be in a satisfactory condition, and for them to have been installed and secured correctly. Additional stresses caused by catalytic converters that have been installed twisted, for example, are also to be avoided.