Fix Your Vehicle's Exhaust Manifold Gasket Leak

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.. The exhaust system 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, rubber and composite materials and are designed to withstand high temperatures, vibrations and pressures. With prolonged exposure to such extreme 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 and can have adverse effects not only on the people sitting in the car but also on the environment. 

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.

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

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.

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. An exhaust leak can hinder the backpressure causing a change in the oxygen sensor reading. This can result in poor fuel economy and performance because the fuel supplied is altered.

Unusual smells from your vehicle is not a good sign. The gas passing through into the exhaust manifold is at very high temperatures. If the exhaust fumes escape directly into the engine bay, it can melt plastics, wires and other such vulnerable components in the engine bay, resulting in a burning smell. This smell can find its way into the cabin as you drive along and can even be accompanied by smoke.

Now that we have understood the signs of a failing exhaust manifold, it is necessary to treat this problem and for that we must know how to fix it. Let’s walk you through the procedure of replacing the exhaust manifold gaskets.

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 its removal with the help of following tools:

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. If a gasket is stuck onto the engine block or manifold, use a plastic scraper to remove it. Apply extra pressure if necessary to loosen it.. 

10. You may now observe black soot around the gasket, manifold and the 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 this case you may require replacing the entire exhaust manifold, and if the engine block is faulty then get it checked 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. Make sure the mating surface is clean before attaching.. 

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.