Fix Your Vehicle's Exhaust Manifold Gasket Leak

What Is An Exhaust Manifold Gasket?

The exhaust system in every vehicle is responsible for transporting the toxic gasses from the cylinder’s combustion chamber to the various components that help detoxify the exhaust fumes, that are otherwise harmful to the environment. It also provides a path for these gasses to exit the vehicle from the rear. The exhaust manifold gasket is the first element in this system that seals the connection between the cylinder opening and the exhaust manifold. 

Exhaust manifold gaskets are made of metal and other composite materials and are designed to withstand high temperatures, vibrations and pressures. With prolonged exposure to such conditions, the manifold gasket is prone to failure. A broken exhaust manifold gasket can be detrimental to the entire engine functioning and neglecting it can cause many issues such as allowing high-temperature gasses directly into the engine bay which can melt plastics and damage components in the engine bay. The gasses leaving the cylinder are untreated and are extremely harmful which can have adverse effects on the driver and passengers along with the environment as well. 

Hence it is imperative to source out this problem before it can proliferate into a larger issue. But how do we know if there is a potential exhaust manifold leak? Well, here are a few symptoms to look out for. 

What Are The Symptoms Of A Leaking Exhaust Manifold Gasket?

These are the signs one must look out for exhaust manifold gasket failure:

Increased Engine Noise

A leak in the exhaust manifold can severely increase the engine and exhaust noise. The sound may start out faint, but over time the engine noise can increase considerably. A characteristic hissing or tapping sound can be heard from the engine bay around the exhaust manifold. The noise becomes more prominent when accelerating and can even be heard in the cabin. If you hear a ticking or hissing sound on cold starts, and the sound dissipates as the engine gets warm, then it is a clear indication of a leak from the exhaust manifold area. 

Decreased Engine Performance And Fuel Efficiency

Leakage at the manifold can directly affect engine performance as the horsepower can take a hit which can be felt when accelerating the engine and during cold starting. Modern vehicles have a monitored system and the exhaust gasses are used to understand how much fuel is to be given in order to reduce emissions and increase performance. A leak can hinder the backpressure causing a change in the oxygen sensor reading, which changes the fuel supplied resulting in poor fuel economy and performance. 

A Burning Or Unusual Smell

The gas passing through into the exhaust manifold is at very high temperatures. If the exhaust fumes escape directly into the engine compartment, it can melt plastics, wires and other such vulnerable components in the engine bay which results in a burning smell. This smell can find its way into the cabin as you drive along and can be accompanied by smoke. 

Now that we have established what the signs are that can enlighten us to a failing exhaust manifold, it is necessary to treat this problem and for that we must know how to fix it. This next section will walk you through the procedure of replacing the exhaust manifold gaskets. 

How To Fix An Exhaust Manifold Gasket Leak?

In order to eliminate this issue, it is necessary to replace the gaskets. To replace the exhaust manifold gasket you will need to remove the exhaust manifold. The placement of the manifold varies in every vehicle. Find the manifold and proceed with the removal with the following tools:

Follow these STEPS for easy removal and refitting of the exhaust manifold gaskets:

  1. Disconnect the negative battery terminal and wait till the engine is cool to touch. 
  2. Hoist the car on a floor jack and support it using jack stands for increased safety. 
  3. Remove the engine and exhaust shielding covers and any connections to the exhaust manifold like the oxygen sensor
  4. Depending on your vehicle the exhaust can be accessed from the top or bottom of the vehicle. You can remove the wheel well cover to access the bolts from the side as well.
  5. Locate all the bolts that secure the manifold to the engine block and to the exhaust downpipe. 
  6. Apply some penetrating oil on the bolts to ease the removal process. 
  7. Undo the bolts using a ratchet and the appropriate socket. Also, undo the bolts on the collector and the downpipe intersection. 
  8. Remove the bolts while holding onto the manifold. Once all bolts are removed, gently lift the exhaust manifold away from the engine and place it on a work surface. 
  9. Remove the gasket which may be stuck onto the engine block or the manifold, with the help of a plastic scraper if stuck on very tightly. 
  10. You may now observe black soot around the gasket, manifold, and engine block. This is the result of leakage which allowed the gasses to form a layer over the metal surfaces. 
  11. Before installing the new gasket, clean the manifold and engine block surface where the gasket sits, with some brake cleaner and a clean towel. This is also a good time to clean any carbon buildup inside the exhaust manifold.
  12. Inspect the surface of contact on both the manifold and the engine opening for any cracks or fissures on the metal surfaces. A cracked manifold can be the real reason for the leakage. In which case you may require replacing the entire exhaust manifold, and if the engine block is faulty then have it looked at by a professional for further analysis. 
  13. Now compare the new and old gaskets to make sure they are an exact match and place the new one on the engine block. Then place the manifold and first hand tighten the bolts and then torque the bolts to the correct torque specifications written in the owner's manual. 
  14. Attach the exhaust downpipe along with the flange gasket underneath making sure to have a clean mating surface. 
  15. Always torque the bolts to the right torque specifications to avoid unnecessarily damaging the gaskets. 
  16. Reinstall all the covers and connections that were previously removed. 


Q) Can You Drive With A Bad Exhaust Manifold Gasket?

While you can drive with a bad exhaust manifold gasket you really shouldn’t. A leak in the exhaust manifold gasket can cause disturbances in the engine by reducing engine performance and fuel efficiency. Since exhaust gases are extremely harmful, untreated exhaust gases can leak through a broken exhaust manifold gasket causing increased emissions. These gases can find their way into the cabin and cause serious safety hazards if neglected for long. Therefore, it is necessary to fix a leak in the exhaust system as soon as possible.

Q) How Long Does An Exhaust Manifold Gasket Last?

The lifespan of an engine exhaust manifold gasket depends on factors such as engine mileage and driving conditions. The manifold gasket is subjected to repeated heating and cooling cycles which can cause premature failure. Along with the high temperatures, the manifold gasket is also exposed to moisture and debris which are all contributing factors to its failure. Most exhaust manifold gaskets can last over 100,000 kilometers.


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John Framigllia
Technical Writer
Our technical writer is known for simplifying automotive parts and services. Intuitive with various vehicles and manufacturers, he knows how to simplify complicated problems.