Repair And Fix it

The exhaust manifold, also known as a header, on the Chevy Lumina collects the exhaust gases from the engine cylinders and diverts them through the exhaust pipe. If the manifold develops cracks, you will need to change it or the efficiency of the engine will drop. This is a project that you can do yourself, so there is no need to take the Lumina to an automotive repair shop. You can expect it to take you about three hours to complete the project.

Instructions

1

Disconnect the negative cable from the battery using a wrench to loosen the terminal nut. Disconnect the wiring harness from the oxygen sensor. Turn the belt tensioner using a wrench and relieve the tension from the serpentine belt. Note the proper routing of the belt if the diagram is missing.

2

Remove the serpentine belt from the Lumina engine. Remove the bolts from the alternator using a socket and ratchet and take it off the engine. Place the wheel chocks behind the rear wheels of the Lumina. Lift the front of the car with the automobile jack. Place the jack stand under the Lumina near the jacking point and raise it to the frame.

3

Remove the bolts retaining the exhaust pipe to the manifold using a wrench. Remove the jack stand from under the Lumina and lower the car to the ground. Remove the oil fill tube from the engine block using a wrench. Pull the tube away from the engine. Remove the nuts from the exhaust manifold using a socket and ratchet. Remove the manifold from the engine.

4

Remove the manifold gasket and discard it. Install a new gasket and exhaust manifold. Secure the nuts using a socket and ratchet. Install the oil fill tube and tighten the nut with a wrench. Raise the Lumina with the automobile jack. Place the jack stand under the car near the jacking point and raise it to the frame.

5

Crawl under the Lumina and connect the exhaust pipe to the manifold. Tighten the bolts with a wrench. Remove the jack stand from under the Lumina. Lower the car to the ground. Install the alternator and tighten the bolts with a socket and ratchet. Install the serpentine belt according to the diagram you made, or the one under the engine hood if present.

6

Place tension on the serpentine belt by turning the belt tensioner with a wrench. Connect the electrical connection to the oxygen sensor. Connect the negative cable to the battery and tighten the terminal nut with a wrench.

Exhaust manifold leaks are obvious, especially when first starting the engine. As the engine warms, the metal of the manifold and engine block expand and quiet the leak. Manifold leaks can vary in sound from a loud exhaust leak to a subtle ticking sound -- often misdiagnosed as a faulty lifter in the valves. In some cases, testing the manifold can require lifting the vehicle. Manifold to block connections can be tested from the engine compartment or under the vehicle. The use of a stethoscope will undeniably pinpoint a leak and its location.

Instructions

1

Park the vehicle on a flat surface and apply the parking brake. Open the hood (even if the vehicle is being lifted to test the manifold, the open hood will offer more lighting to see better underneath the vehicle). If there is no need to lift the vehicle to test the manifold to block connection, proceed to Step 4.

2

Place a wheel chock against the outer tread of one of the rear tires for extra protection (if lifting the vehicle).

3

Hoist the front of the vehicle up with a jack and place it onto jack stands (one side at a time).

4

Put on the safety glasses and gloves and then start the engine.

5

Put the stethoscope on (and crawl under the hoisted vehicle, if applicable) and run the tip of the stethoscope along the manifold to engine block connection. Be aware of moving engine parts and loose fitting clothes; especially if testing from the engine compartment area. Also be aware that it will not take long for the front exhaust system to get extremely hot. Be sure arms and hands are well covered and protected.

6

Check the manifold to engine block connection thoroughly. The moment the tip of the stethoscope gets near a leak, the sound will intensify greatly. Check for leaks in other locations along the manifold to block connection and even check the front exhaust pipe to manifold connection.

As the engine in your Jeep Comanche runs, hot exhaust gases are expelled from the combustion chamber into the exhaust manifold. The gases are kept in check by a series of exhaust gaskets, most notably the exhaust manifold gasket. If the exhaust manifold gasket is damaged or leaking, the engine will produce excessive noise, and the exhaust gases will escape into the engine compartment instead of exiting out the tailpipe as they should. Replacing the gasket is fairly straightforward, and you will need only a few tools to complete the job.

Instructions

1

Raise the hood of your Comanche and prop it open. Remove the negative cable from the battery by turning the bolt counterclockwise with the wrench.

2

Locate the exhaust manifold bolts and spray them with the penetrating oil. The bolts are usually corroded into place, so if possible allow the oil to soak into the bolts for a few hours.

3

Loosen the exhaust manifold bolts by turning them counterclockwise with the socket. Pull the exhaust manifold from the engine. Remove any of the old gasket with the scraper.

4

Coat the exhaust manifold bolts with anti-seize compound. Slide the new gasket into place between the exhaust manifold and the engine. Tighten the exhaust manifold bolts by turning them clockwise with the socket. Start with the inside bolts and work toward the outside as you tighten.

5

Reattach the negative cable to the battery by turning the bolt clockwise with the wrench. Start the engine and check for exhaust leaks.

First produced in 1968, the Ford 460 used a pair of one-piece exhaust manifolds to direct the engines exhaust gases to the exhaust pipes. Between the cylinder head and the exhaust manifold is a gasket designed to prevent exhaust leaks. When the gasket fails, often a puffing sound can be heard as the exhaust gases leak out of the manifold. More often than not, however, the first indication of a manifold leak is the strong odor of dangerous exhaust gases inside the vehicle. For this reason, a new gasket should be installed immediately.

Instructions

1

Remove the exhaust manifolds securing nuts or bolts with a socket wrench and with an open-end wrench. Although the design of the 460s exhaust manifold remained the same throughout its production, there were variations of its fasteners. Some manifolds used only retaining bolts, while others instead featured studs and nuts. With either design, both types of wrenches are necessary to remove the fasteners. Use the open-end wrench to access the fasteners that the socket wrench cannot access.

2

Pull the exhaust manifold off the cylinder head to access the manifolds gasket. Tap on the bottom of the manifold with a rubber mallet to dislodge it if the manifold is stuck.

3

Peel the exhaust manifold gasket off of either the cylinder head or the manifold, depending on which surface the gasket adhered to. The portion of the gasket which failed can be identified by a black burn mark.

4

Position a new exhaust-manifold gasket onto the manifold or, if the engine instead features studs, slide the gasket onto the studs and against the cylinder head. The 460s exhaust-manifold gasket is self-sealing, meaning that gasket sealant must not be applied to the gasket.

5

Place the exhaust manifold against the cylinder head, then tighten the exhaust manifolds fasteners to between 30 and 35 ft-lbs. of torque with a torque wrench.

An exhaust leak can be frustrating. While exhaust leaks are often difficult to identify, worn exhaust manifold gaskets are often the problem. Removing worn exhaust manifold gaskets and replacing them with new gaskets on a Buick LeSabre is a small, inexpensive project for a do-it-yourself mechanic. With a few tools and a bit of time, you can remove failing exhaust manifold gaskets and replace them with new gaskets to increase the performance of your Buick LeSabre.

Instructions

1

Allow the engine and exhaust manifold to completely cool.

2

Disconnect any tubing from the exhaust manifold.

3

Loosen and remove the exhaust manifold bolts. If the bolts are resistant, use a penetrating oil to loosen them.

4

Remove the exhaust manifold and gaskets from the engine. The exhaust manifold in a Buick LeSabre is typically secured with two studs and two nuts.

5

Clean the gasket areas on both the engine and exhaust manifold with a scraper and wire brush to remove any remaining material from the old gasket. A clean, smooth surface ensures proper installation of the new gaskets.

The intake manifold on old engines provides the entryway of fuel and air into the engine and eventually the combustion chamber, where it turns to energy, powering the engine parts. Identifying this critical channel is fairly easy on old engines, since its connected to the carburetor, which performs the air-fuel mixing prior to going into the engine.

Instructions

1

Park the car in a place that is easy to work in if the car can be moved. Lift the car engine hood and prop it up to stay open on its own. Locate the carburetor assembly on top of the V-8 engine.

2

Use a flashlight to help see the engine parts if you cant see well with the regular room or area light. Locate the exit side of the carburetor where the air-fuel flow will go to the engine. Look opposite the side of the air filter and fuel lines connected to the carburetor.

3

Follow the carburetor to the metal tubular channels that go from the carburetor into the engine casing itself -- this is the intake manifold. Note how the manifold is bolted to the engine case to maintain its connection.

4

Check underneath the engine if the intake manifold is not visible from the top exiting the carburetor unit. Look for a manifold that enters the engine from the side after looping downward vertically from the carburetor.

The 3800 engine is a six-cylinder, 3.8-liter engine manufactured by General Motors. The Series II version of this engine was in production from 1996 to 2005, and appeared in various Buick cars during this period. The 3800 Series II engine contained many changes over the Series I engine, including a new intake manifold that improved the engines breathing. This intake manifold consisted of an upper and lower portion which are composed of cast iron.

Instructions

1

Remove the negative battery cable with a socket wrench to prevent the discharge of fuel. Place a pan under the radiator drain, and open the drain cock. Drain the coolant from the radiator, and store the coolant for later use. Replace the drain cock.

2

Remove the cap on the fuel tank to relieve the pressure in the tank. Wrap a shop rag around the pressure test port on the fuel rail to absorb spilled fuel. Connect a fuel pressure gauge to the test port, and place the bleed hose in a gasoline container. Open the valve on the fuel pressure gauge to relieve the pressure in the fuel system. Remove the shop rag and fuel pressure gauge from the fuel rail.

3

Disconnect the sight shield from the fuel injector with a socket wrench. Remove the air inlet duct and electrical wiring to the spark plugs on the right side of the engine. Disconnect the Manifold Absolute Pressure (MAP) sensor and the vacuum lines from the intake manifold. Detach the electrical connectors from the fuel injectors, and disconnect the fuel lines from the fuel regulator.

4

Detach the fuel rail and Exhaust Gas Recirculation (EGR) heat shield from the intake manifold with a socket wrench. Disconnect the bracket for the throttle cables and remove the throttle cables from the throttle body lever. Remove the upper intake manifold from the engine.

5

Install the new upper intake manifold to the engine, and tighten its mounting bolts to 88 inch-pounds with a torque wrench. Connect the throttle cable bracket and throttle cable to the throttle body lever with a socket wrench. Connect the EGR heat shield and fuel rail to the intake manifold. Tighten the mounting bolts for the fuel rail to 88 inch-pounds. with a torque wrench.

6

Connect the fuel lines to the fuel rail and fuel regulator. Attach the electrical connectors for the fuel injectors, and connect the vacuum lines to the intake manifold. Connect the electrical wiring for the MAP sensor and spark plugs. Connect the sight shield for the fuel injector and the air inlet duct with a socket wrench.

7

Fasten the fuel tank cap, and fill the radiator with coolant. Attach the negative battery cable with a socket wrench and start the engine. Correct any coolant or fuel leaks.

The exhaust manifold on a Dodge Caravan is responsible for getting the exhaust gasses created by the engine out of the cylinder head and into the exhaust tubing. The manifold is made of cast iron, which can crack under certain atmospheric conditions, or when cold water is applied to a hot manifold. When that happens, the exhaust will come out of the manifold and not out of the exhaust pipe itself, which will make an annoying noise and potentially cause a loss in horsepower.

Instructions

1

Raise the front end of the Caravan with the jack and place a pair of jack stands underneath the front of the chassis. Unbolt the exhaust from the exhaust manifold using the 3/8-inch ratchet, extension and sockets.

2

Unbolt the EGR tube and crossover pipe from the exhaust using an open-end wrench. Unplug the oxygen sensor connection by hand, then remove the oxygen sensor with the oxygen sensor wrench.

3

Unbolt the heat shield from the exhaust manifold using the 3/8-inch ratchet and socket, then unbolt the manifold from the engine with the ratchet. Pull the manifold off of the engine and out of the engine compartment. Remove the exhaust manifold gasket as well.

4

Scrape the mounting surface on the cylinder head using the gasket scraper. Slide the replacement gasket and manifold onto the engine and bolt it in place from the center of the manifold outward using the 3/8-inch ratchet, extension and sockets. Apply a thin coat of the anti-seize compound to the threads of the oxygen sensor, then install the sensor into the manifold.

5

Reconnect the crossover pipe, EGR tube and exhaust to the manifold with a 3/8-inch ratchet and socket. Then reinstall the heat shield with the ratchet. Lower the van off of the jack and jack stands.

Preparation

Before the exhaust manifold on a Jeep Grand Cherokee can be installed, the vehicle must be prepped. The battery and air cleaning assembly, including the filter, must be removed; and all coolants, such as windshield cleaning solution and radiator fluid, should be drained and flushed from the system. Disconnect the air-conditioner and detach the starter motor and all heating hoses. You are removing them to gain access to the cylinder head.

Removing Existing Parts

Remove the manifold by, first, taking out the heat-shield components and disconnecting the starter motor. Detach the Y-pipe, and unbolt and lift out the manifold, along with the gasket between the unit and the engine. Rusty bolts and fasteners are usually treated and cleaned before the new manifold is installed.

Installation

Before the exhaust manifold is attached to the cylinder head, covering all six cylinders, position the manifold gasket over the edge of the opening. Then set the manifold into place over the gasket. Tighten the bolts, starting in the center and moving toward the ends, and reconnect the unit to the Y-pipe. Reinstall the disassembled parts in the opposite order in which they were removed.