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What causes exhaust manifold to go bad?


The exhaust manifold is a crucial component of your vehicle's exhaust system, responsible for directing exhaust gases from the engine to the exhaust pipe. Over time, various factors can lead to the deterioration of the exhaust manifold, resulting in performance issues and increased emissions. In this article, we will explore the common causes of exhaust manifold failure and what you can do to prevent it.


Common Causes of Exhaust Manifold Failure


Understanding the reasons behind exhaust manifold failure can help you take proactive measures to maintain your vehicle. Here are some of the primary causes:



  • Heat Stress: The exhaust manifold is subjected to extreme temperatures, which can cause metal fatigue over time. Repeated heating and cooling cycles can lead to cracks and warping.

  • Corrosion: Exposure to moisture and road salt can lead to rust and corrosion, particularly in older vehicles. This deterioration weakens the manifold and can lead to leaks.

  • Improper Installation: If the exhaust manifold is not installed correctly, it can lead to uneven stress distribution, increasing the likelihood of cracks and breaks.

  • Engine Overheating: An overheating engine can cause excessive heat in the exhaust manifold, leading to warping and failure. Regular maintenance can help prevent overheating issues.

  • Exhaust Leaks: If there are leaks in the exhaust system, it can create additional pressure on the manifold, leading to premature wear and tear.


Signs of a Failing Exhaust Manifold


Being aware of the signs of a failing exhaust manifold can help you address issues before they escalate. Look out for the following symptoms:



  • Increased engine noise, particularly a loud hissing or tapping sound.

  • Decreased engine performance or power.

  • Visible cracks or damage on the manifold.

  • Excessive exhaust fumes or a strong smell of exhaust inside the vehicle.

  • Check engine light illuminated on your dashboard.


Preventive Measures


To extend the life of your exhaust manifold and avoid costly repairs, consider the following preventive measures:



  • Regularly inspect your exhaust system for signs of wear and tear.

  • Ensure proper installation of the exhaust manifold and related components.

  • Maintain your engine's cooling system to prevent overheating.

  • Use high-quality parts during repairs and replacements.

  • Schedule routine maintenance checks with a trusted mechanic.


By understanding the causes of exhaust manifold failure and taking proactive steps, you can help ensure your vehicle runs smoothly and efficiently for years to come. If you suspect issues with your exhaust manifold, don't hesitate to contact a professional for an inspection.


Frequently Asked Questions

How does an exhaust manifold fail?


An exhaust manifold crack is caused by one of 2 reasons. The first one being the heat cycles the manifold experiences. Over a significant period of time, these cycles take their toll on the manifold and it just gets to a point where it can't take the heat anymore.



What breaks exhaust manifold?


Under extreme use like towing heavy loads, the exhaust manifolds can go from normal operating temperature to cherry red in a matter of seconds. That rapid heat causes the exhaust manifold material to expand, which puts a tremendous strain on the bolts and/or studs holding the manifolds to the cylinder heads.



Is it worth replacing exhaust manifold?


As cracks form in the cast iron structure, your vehicle's performance will suffer. Replacing the cracked exhaust manifold with an aftermarket manifold will restore and improve your vehicle's performance.



What causes exhaust manifolds to go out?


The manifold itself can also crack or warp due to exposure to extreme heat over time. It's also possible for the bolts holding the manifold in place to loosen or fall out, causing a leak; this issue is most likely a manufacturing defect rather than something caused by the vehicle's age or condition.



Is it worth replacing an exhaust manifold?


As cracks form in the cast iron structure, your vehicle's performance will suffer. Replacing the cracked exhaust manifold with an aftermarket manifold will restore and improve your vehicle's performance.



What causes damage to the exhaust manifold?


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. Worn-out gaskets.



How much does it cost to replace an exhaust manifold?


between $1,239 and $1,350
The average cost for an Exhaust Manifold Replacement is between $1,239 and $1,350. Labor costs are estimated between $244 and $308 while parts are priced between $994 and $1,042. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.



Can you drive with a bad exhaust manifold?


It's best to avoid driving your car until you have repaired or replaced its faulty exhaust manifold gasket. The reduction in fuel efficiency can make you drop by the gas station more often to fill your fuel tank. And if your vehicle is slated for an emissions test, it's going to fail.



What is the life expectancy of an exhaust manifold?


Most experts suggest that a manifold will have a life expectancy of six to eight years. However, heavy use in saltwater can see this drop to as low as three years, while lightly used freshwater boats can get up to 20 years out of a manifold. (We are assuming that your manifold is raw water cooled.



Is it expensive to fix an exhaust manifold?


The average cost for an Exhaust Manifold Replacement is between $1,239 and $1,350. Labor costs are estimated between $244 and $308 while parts are priced between $994 and $1,042. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.


Kevin's Auto

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.