Popping or Hissing noise?

Popping or Hissing Noises From The Engine Compartment?

Many things can contribute to popping and or hissing noises while your engine is running. The most likely cause of these kinds of noises are related to exhaust issues. Most commonly issues with the exhaust manifold where exhaust gasses exit the vehicle. Today were going to discuss what an exhaust manifold is and what it's job is on your vehicle!

What is an exhaust manifold?

There are many components that make up an exhaust system, but one of the most important parts of that system is the exhaust manifold. The manifold is designed to route the toxic gases that come from an engine and send them through the rest of the exhaust system for cleaning and safe release from the vehicle. Exhaust manifolds are made out of cast iron or stamped steel, the reason being is these materials handle extreme heat temperatures. Average exhaust temperatures range from 400 degrees Fahrenheit to 500 degrees Fahrenheit. Constant heating up and cooling down will weaken the materials and overtime broken bolts or damaged manifold gaskets will cause a leak from the manifold.

What are symptoms of an exhaust manifold leak?

-Strange Noises

A hissing or a puffing noise is usually an indicator of a manifold leak. More often than not the bolts that secure the manifold to the cylinder head will break and no longer secure the manifold to the head and exhaust gasses will escape causing an abnormal noise.

-Loss Of Fuel Economy

A drop in fuel efficiency can be a sign of an exhaust manifold issue. If you have noticed a loss of fuel economy or find yourself filling up your vehicle more often than your used to you may want to have the exhaust manifold inspected by a professional.

-Funny Smells

When an exhaust manifold has a leak sometimes the exhaust gasses will make it into the cabin of the vehicle causing a smoky or musty smell.

-Loss Of Power or Acceleration

A manifold leak can make your car feel like it’s not accelerating or has less power than what your used to.

-Check Engine Light

The exhaust system is monitored by sensors to determine if your vehicle is running normally base on the gasses that are present in the exhaust system. When an exhaust system has a leak the normal amount of gasses are no longer present in the system and will cause a check engine light to come on because the sensors have noticed an abnormal condition.

Are exhaust manifolds difficult to replace?

There are a couple different variables that come into play when replacing an exhaust manifold. It depends on where it is leaking from and how long it has been leaking. The most common type of exhaust manifold issue is broken manifold bolts. Overtime and throughout the constant heating and cooling of the manifold and its securing bolts they start to become weak. When bolts break the manifold must be removed and either drilling out the broken exhaust manifold bolt & extracting them with a bolt extractor. Depending on how many bolts are broken will affect the cost of replacement. If a broken manifold bolt is not addressed soon enough the heat from the exhaust system will warp the manifold resulting in a new exhaust manifold being needed.


Commitment to Excellence!

Exhaust issues and repairs can be frustrating and expensive without proper training and tools. This type of issue is strongly recommended to be checked out by a professional. At Dickerson Automotive we set the professional bar. With constantly updated equipment and an extensive knowledge of car repair we offer the best repair shop experience. If your car has any of these symptoms or even for questions regarding exhaust systems give us a call!



  1. https://wrench.com/blog/everything-you-need-to-know-about-an-exhaust-manifold-leak/

  2. https://www.cars.com/auto-repair/glossary/exhaust-manifold/#:~:text=Bolted%20directly%20to%20the%20engine,manifold%20for%20each%20cylinder%20bank.

  3. https://getjerry.com/questions/how-hot-does-a-car-exhaust-pipe-get