6 Signs That You Have an Exhaust Manifold Leak

What are the signs that you have an exhaust manifold leak?

  1. Strange noises
  2. Toxic and burning smell
  3. Check engine light is on
  4. Poor performance
  5. Less efficient fuel economy
  6. Physical damage


An exhaust manifold is a part of your vehicle’s exhaust system, directly bolted to the engine block. Its main role is to take the exhaust gases to the catalytic converter, where harmful substances such as nitrogen oxides, carbon monoxide, and hydrocarbon are converted into less harmful ones. But if there is a problem with your exhaust manifold, toxic gases can leak out, putting your health at risk and causing problems for your vehicle. For this reason, you need to know the top exhaust manifold leak signs. Read on!


Strange Noises

As a vehicle owner, you need to train your ears to differentiate the sound of a well-maintained car and one that has issues. For instance, one of the signs that you need to check your exhaust manifold is if you’re hearing strange noises. Cracks and loose parts will cause a leak that creates a tapping or hissing sound.

The noise will be its loudest during a cold start and may diminish as the engine warms up. This is because the manifold will expand, which causes the leak to close temporarily.


Toxic and Burning Smell

Toxic and Burning Smell

Exhaust gases are supposed to go through the entire exhaust system. That’s why, if you have an exhaust manifold leak, you might notice a toxic smell. This is because the harmful gases have escaped into the air before going into the catalytic converter to be converted to be a less harmful gas.

As the first section of your vehicle’s exhaust system, the gases are still extremely hot coming from the combustion chamber. This can be the reason why you’ll also notice a burning smell. Other than the odor, this could also cause premature wear and physical damage to other components of your engine.

When you notice the toxic and burning smell, there’s also a chance that exhaust fumes are already present inside the cabin, which can affect your health.


Check Engine Light Is On

There are many reasons why your check engine light is on. It could be because you have a faulty gas cap that allows the fuel vapors to escape into the air. Or maybe the spark plugs are worn out. But another reason is because of an exhaust manifold leak.

When you have a leak in your exhaust manifold, the oxygen sensors in your vehicle will see the situation as a lean running condition. This usually happens when there’s too little fuel in the air-fuel mixture. But in this case, the sensor is misinterpreting the leak. When this happens, you’ll notice that your check engine light is on.


Poor Performance

Poor Performance

One of the signs that you need to bring your vehicle to the mechanic is if you notice a loss of acceleration. This can impact your daily driving experience, so it’s recommended to have your car checked immediately.

An exhaust manifold leak will cause poor performance because it can affect the fuel delivery of your vehicle. In some cases, the engine computer will respond to the perceived lean running condition by making the air-fuel mixture richer — which can cause misfiring.


Less Efficient Fuel Economy

Aside from the sounds, smell, and performance, an exhaust manifold leak will also affect your wallet negatively. By tricking the oxygen sensor that the engine has a lean mixture, the engine control unit (ECU) will increase the fuel delivery to make up for the low amount of fuel. Not only will this compromise the performance of your vehicle, but also cause poor fuel mileage.

That’s why if you notice that you’re going to the gas station more often than usual, you might want to get your vehicle checked for a potential exhaust manifold leak.


Physical Damage

Physical Damage

One of the easiest ways to confirm that you have an exhaust manifold leak is to perform a visual inspection. Check the component for signs of damage before attempting a repair.

For instance, the studs or bolts might have weakened or failed over time, which causes a loose connection for the manifold and the cylinder head. In some cases, you might realize that the studs are already missing. This can happen when the manifold has warped, causing the studs to break.

Other than that, leaks can come through when there are cracks or melting on the manifold. If you see soot stains, then it’s a telltale sign that there’s already a leak.


Key Takeaway

If you spot these exhaust manifold leak signs, it’s a good idea to call a mechanic that can inspect and repair the problem. In case the damage is severe, you might need to have a replacement instead to prevent the symptoms from happening again. A leak cannot just cause performance issues, but also put your health at risk.

If you’re looking for automotive parts for your vehicle, you can contact us here at Roberts! From exhaust manifolds, catalytic converters, mufflers, pipe tail, and more — we have it here.