Should i replace exhaust manifold gasket

The exhaust manifold collects the post-combustion gases from multiple cylinders and routes them into the exhaust pipe. The manifold is attached to the cylinder head, and the unit is sealed with the use of an exhaust manifold gasket. Extreme temperatures, oil, coolant contamination, and the constant barrage of exhaust gas will wear the gasket to the point where leaks will develop between the cylinder head and manifold.

In the simplest terms, it helps the engine breathe. The engine is just a giant air pump, and the better the pump works at sucking in air and sending it out, the better the car drives. Leaks reduce the velocity of the exhaust stream, so your engine loses power. While this issue will not leave you broken down waiting for a tow truck, the repair may take some time. Each vehicle will have different parts that are in the way of the exhaust manifold gasket.

Refer to your vehicle service manual for exact steps on how to remove these components. Step 4: Remove heat shield. To remove the heat shield in most cases, you'll need to unscrew two to four bolts that are on top or to the side of the exhaust manifold. Refer to your vehicle service manual for exact instructions.

Step 5: Spray the exhaust manifold bolts or nuts with penetrating fluid. To avoid stripping nuts or breaking the studs, apply a liberal amount of penetrating oil on each nut or bolt that holds the exhaust manifold on the cylinder heads.

Wait five minutes before you attempt to remove these nuts so the fluid can soak into the stud. After completing this step, crawl underneath the vehicle or if the vehicle is raised on a rack, spray the bolts connecting the exhaust manifold to the exhaust pipes. Most of the time, there will be three bolts connecting the exhaust manifold to the exhaust pipes.

Spray penetrating fluid on both sides of the bolts and nuts and let it soak in while you remove the top portion. Step 6: Remove the exhaust manifold from cylinder head. Remove the bolts that secure the exhaust manifold to the cylinder head. Using a socket, extension and a ratchet, remove the bolts in any order however when you install the new manifold after replacing the exhaust manifold gasket, you'll need to tighten in a specific order.

Step 7: Remove exhaust manifold from exhaust pipe. Use a boxed end wrench to hold onto the bolt and a socket to remove the nut or vice versa depending on your ability to access this part and remove the bolts that secure the two exhaust systems. Remove the exhaust manifold from the vehicle after completing this step. Step 8: Remove old exhaust manifold gasket. Once the exhaust manifold has been removed from the vehicle, the exhaust manifold gasket should easily slide off.

However, in some cases, the gasket will be fused to the cylinder head due to excessive heat. If this is the case, you'll need to use a small scraper to pry the gasket off the cylinder head. Step 9: Clean the exhaust ports on the cylinder head.

Using a can of carb cleaner, spray onto a clean shop rag and then wipe the insides of the exhaust ports until the port appears to be clean. You should also use some steel wool or very light weight sandpaper grit and lightly scrub the outsides of the ports to remove any pits or residue on the outside of the exhaust port.

Again, if the cylinder head looks discolored or is damaged, remove the cylinder heads and have them inspected or repaired by a professional machine shop. After installing the new gasket, you'll have to install the bolts holding the exhaust manifold onto the cylinder heads in a certain pattern. Please refer to the service manual of your vehicle for exact instructions and recommended torque pressure settings for reinstalling a new exhaust manifold. Step Install the new exhaust manifold gasket.

The steps for installing the new exhaust manifold gasket are in reverse of the removal steps as indicated below:. Apply anti-seize to the studs on the cylinder heads that attach the exhaust manifold to the cylinder head. Attach the exhaust manifold to the exhaust pipes below the vehicle after applying anti-seize to each bolt. Hand-tighten each nut onto the cylinder head studs in the precise order as instructed by the vehicle manufacturer until each nut is hand-tight and the exhaust manifold is flush against the cylinder head equally.

Tighten exhaust manifold nuts to the require torque pressure and in the exact pattern as recommended by the vehicle manufacturer. Reattach engine covers, coolant lines, air filters and other parts that were removed to gain access to the exhaust manifold. Some water-heated intake manifolds, particularly on V-engines , require gasket sealant on each side of the gasket, because the larger water passages are more prone to leakage.

Reassembly is in the reverse order of removal. Tighten the nuts on the manifold, using a torque wrench adjusted to the setting recommended in the car service manual. The tightening sequence is usually from the centre of the manifold outwards to the ends.

After reassembly, run the engine to working temperature, switch it off and check the torque settings. Remove the air cleaner.

Make a careful note of all the connections to the carburettor. Disconnect the choke and throttle cables to the carburettor. Then take off the fuel pipe. If possible, keep the disconnected end of the fuel pipe higher than the level of fuel in the fuel tank. If the carburettor has an automatic choke, disconnect the water pipes or wires at the choke.

You may have to remove the carburettor completely See Removing a carburettor for cleaning before you can remove the manifold. If so store it upright in a clean place. Take care not to damage the carburettor mounting block, which may be made of rubber or a composition material, and acts as a gasket. Please see our terms of service for more details. Excellent Auto Repair Ratings. YourMechanic Auto Repair. Related Articles. Where Is the O2 Sensor Located? How Does a Muffler Work?

Experienced Mechanic? Recent Exhaust Manifold Gasket Replacement reviews. Excellent Rating. Rating Summary. Joel 21 years of experience.

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