How to Fix an Exhaust Manifold Gasket Leak?
What is an Exhaust Manifold Gasket?
The Exhaust system in every vehicle is responsible for transporting the spent gasses from the cylinder’s combustion chamber to the various components that help detoxify these gasses, that are otherwise harmful to the environment, and provide a path for these gasses to exit the vehicle from the rear. The exhaust manifold gasket is the first element in this system which seals the connection between the cylinder opening and the exhaust manifold and between the exhaust manifold and exhaust downpipe.
These gaskets are made of metal and other composite materials and are designed to withstand high temperatures and pressures. But with prolonged use, the gasket is prone to failure due to the extreme workload and stress they face. A broken exhaust gasket can be detrimental to the entire engine functioning and neglecting a failure of this capacity can render 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 bigger, 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:
Symptoms of a leaking Exhaust Manifold Gasket
These are the signs one must look out for Exhaust Manifold Gasket failure:
- Decreased Engine Performance: A 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, but a leak can hinder the backpressure causing a change in the sensor reading, leading to input faulty readings resulting in reduced fuel efficiency.
- Increased Engine Noise: The engine may sound loud but it is pretty tuned and low. But when there is a leak in the exhaust manifold gaskets, the sound produced is drastically increased and a hissing or tapping sound emanates from the engine bay. This noise can be more prominent when accelerating and can be heard even in the cabin.
- A Burning or Unusual Smell: The gas passing through into the exhaust manifold is at very high temperatures. If these gasses escape directly into the engine bay, it can melt plastics and wirings and other such vulnerable components in the engine bay which results in a burning smell. This smell can find its way into the cabin and stink up the whole car and are very harmful to humans.
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:
- Disconnect the negative battery terminal and wait till the engine is cool to touch.
- Hoist the car on a floor jack and support it using jack stands for increased safety.
- Remove the engine and exhaust shielding covers and any connections to the exhaust manifold like the oxygen sensor.
- 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.
- Locate all the bolts that secure the manifold to the engine block and to the exhaust downpipe.
- Apply some penetrating oil on the bolts to ease the removal process.
- Undo the bolts using a ratchet and the appropriate socket. Also undo the bolts on the collector and the downpipe intersection.
- 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.
- 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.
- 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.
- 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 build up inside the exhaust manifold.
- Inspect the surface of contact on both the manifold and the engine opening for any cracks or fissures on the metal surfaces which may 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.
- 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.
- Attach the exhaust downpipe along with the flange gasket underneath making sure to have a clean mating surface.
- Always torque the bolts to the right torque specifications to avoid unnecessarily damaging the gaskets.
- Reinstall all the covers and connections that were previously removed.