An exhaust manifold performs a single but vital function on your car and takes gases from the engine through to the exhaust pipe. Since these gases are poisonous, this is highly important. However, from time to time, the gasket on the manifold will need replacing which involves removing the exhaust manifold completely. You’ll also need to remove the exhaust manifold if you’re replacing the engine or taking out the entire exhaust system. It’s not a difficult job and require only a basic grasp of mechanical skills
Step 1 - Raising the Vehicle
Have your car on flat ground and make sure that the engine is cold. Put chocks behind the rear wheels of your vehicle. Make sure it’s in "Park" mode and that the handbrake is on. With a floor jack, raise the front end of the vehicle using the frame for full support. Once lifted. the vehicle can rest on jack stands for optimum safety. Always double-check to be certain the vehicle is stable. It is now safe to get under the vehicle. Spread an old blanket on the ground unless you have a mechanic’s creeper. You should also put gloves on to keep the dirt off your hands.
Step 2 - Exhaust Pipe
Your next job is to remove the exhaust system from the exhaust manifold. Look under the car and you’ll see that the system is connected to the manifold by 2 or 3 bolts. Loosen these with a wrench; you might need to use penetrating oil on them first. Pull the exhaust system away from the manifold so you have room to work on it. If it’s easier, take off the entire exhaust system as this will give you all the room that you need.
Step 3 - Removing the Manifold
You’ll see that each exhaust manifold pipe is attached to the main cylinder by 2 bolts. Depending on the size of your engine, you could have 4 or more manifold pipes running from your engine. All of these have to be taken out to remove the exhaust manifold.
You’ll need to loosen all the bolts and remove them. Go pipe by pipe and if the bolts are reluctant to turn, use a squirt of penetrating oil. Allow it to soak into the bolt before trying again. As you remove each pipe, make a note of where it goes on the cylinder. This will make re-attaching the pipe much easier. Draw a diagram and number each pipe.
In some cases, the pipe will seem stuck to the cylinder. When this happens, tap the exhaust manifold pipe lightly with a rubber mallet. This will help you remove it.
Step 4 - Gasket
When the exhaust manifold pipes are gone, you’ll be able to see the manifold gasket. To complete the removal, this needs to be removed as well. It should peel away from the cylinder but if it does stick, peel it away with a scraper and clean the area thoroughly. This is important because when you put a new gasket on, it needs to sit on bare metal in order to make a good seal.