Repair And Fix it

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.

Fuel injectors operate in conjunction with a high pressure fuel system. The fuel injector head is connected to the fuel line and engine through a O-ring seal. The O-ring allows the injector to be seated, in both the fuel line and engine, without requiring bolts, screws or threaded connectors. Injector leaks stemming from poor O-ring connections may be caused by O-ring shrinkage, exposure to high heat, chemical decomposition, or tears in the O-ring material. Leaks coming directly from the injector require full injector replacement. Replace O-rings whenever an injector is removed from the fuel line or engine, for best results.

Instructions

1

Pressurize the fuel system by turning the ignition key to the "electronics only" mode. The fuel pump will turn on pressurize the fuel lines. If in doubt, turn on the vehicle briefly.

2

Lift the hood. Inspect the fuel injectors and connections for leaks. If fuel is leaking from the injector seal at the fuel line -- the point at which the injector connects to the fuel rail -- the leak is most likely due to O-ring failure. If the fuel is leaking directly from the injector, the injector needs to be replaced. Fuel leaks inside the engines cylinders, often reported by the on-board computer as lean or rich conditions, will require injector replacement.

3

Depressurize the fuel system. Remove the plug to the fuel safety cut-off switch, if equipped, to disable the fuel pump. Fuel safety cut-off switch locations can be found in the vehicles owners manual. Attempt to start the vehicle several times to use any remaining fuel. Remove the ignition key and disconnect the battery.

Injector Removal

4

Remove any vehicle components restricting access to the fuel line. Air intakes, electronics, vacuum hoses and components should all be carefully labeled to ensure they are correctly reinstalled when you are finished servicing the vehicle. Disconnect the fuel injector plug.

5

Disconnect the fuel rail from the fuel injector. Some fuel rails are bolted to the engine. Remove any bolts which prevent removal of the fuel rail. Pull the rail directly away from the fuel injector to disengage the seal. A small amount of fuel may spill from the rail, once the rail is lifted from the injector. Wipe up any fuel before continuing.

6

Grasp the injector with your hands, to avoid tool damage to the injector, and pull directly away from the engine to remove the injector. Rock the injector if the seal is tight. You may feel a slight popping sensation when the injector releases.

7

Inspect the fuel injector for physical damage. Cracked or damaged injectors should be replaced.

8

Remove the O-rings from the top and bottom of the injector. Clean the injector head and nozzle with a brake parts cleaner saturated cloth and allow to dry.

Leak Fixing

9

Install new O-rings on the removed injectors. Coat the O-rings with a small amount of motor oil. The motor oil will lubricate the O-rings during installation to help prevent small tears during the seating process and help prevent the breakdown of the O-ring during use. Slide an O-ring over each end of the injector until the O-ring is seated in the gap provided for the seal.

10

Grasp the injector with your hand and push the injector into the injector hole on the engine. You may feel a small pop as the injector becomes seated. When correctly installed, the injector will resist removal.

11

Press the fuel line onto the injector head, until it is firmly seated.

12

Reconnect the fuel injector plug. Reattach the fuel rail to the engine, if required. Connect any engine components initially removed to provide access to the fuel injectors. Connect the battery.

13

Reconnect the fuel safety cut-off switch, if disabled. Turn on the vehicle for 15 seconds to allow the fuel lines to pressurize. Check for leaks. Start the vehicle to confirm installation.

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.

Precisely locating an exhaust leak determines how it best can be sealed. Typical exhaust systems are clamped or welded at vital connection points. The nature of the exhaust system and the overall condition of the system determines when leaks can be sealed and when replacement parts must be installed. Wear safety glasses to prevent rust and dust associated with exhaust pipes from entering your eyes. Inspect for exhaust leaks with the vehicle running in a well-ventilated area.

Instructions

1

Inspect under the hood where the exhaust manifold meets the engine block. Look for soot or burned paint. Listen for hissing or popping noises, and inspect the manifold for cracks. Either replace the manifold gasket or if the manifold is cracked, replace the manifold itself.

2

Inspect where the manifold or header meets the exhaust pipe. A round graphite gasket often seals the exhaust at this joint. Look for soot, feel for hot gases, and listen for noise around the joint. Replace the gasket, if needed.

3

Turn on a flashlight and use it to examine the exhaust pipe under the vehicle, starting at the front and moving toward the rear bumper. Scrape rusty spots using the screwdriver to see if rust goes through the pipe, or is just on the surface. For large rusty areas use the joint pliers and attempt to gently "squish" the pipe. If it bends under light pressure, replace that section. If only a small hole is present, wrap muffler tape around the pipe, covering the hole to seal the leak.

4

Inspect the joints where pipe meets the catalytic converter and muffler. Listen for noises, and feel for hot gases. Test clamps for tightness if clamped, and replace rusted clamps if necessary. Inspect welds if welded, and test the integrity of the pipe on both sides of the component before attempting to re-weld.

5

Inspect the components themselves. If a catalytic converter or muffler has a hole in it, replace it. Most often, attempts at repairing these components are expensive and unsuccessful. Ensure that all clamps and hangers are tight, and reinspect for leaks after installation of new components.

An exhaust leak can negatively effect the performance and efficiency of your vehicle, as well as lead to safety hazards for the driver and passengers. For this reason, you should diagnose and repair the exhaust system immediately when you experience symptoms of an exhaust leak. To eliminate leaks, the exhaust system must be free of piping damage, and all of the exhaust flange bolts must be extremely tight.

Safety Hazards

Exhaust gasses contain carbon monoxide and other chemicals that are hazardous to human health. The exhaust system is designed to expel these gasses out the rear of the vehicle while reducing noise. If an exhaust leak occurs somewhere along the exhaust system, the gasses can seep into the interior vehicle cabin. This can be hazardous, or even fatal to vehicle passengers due to the buildup of carbon monoxide.

Performance Issues

The exhaust system piping is designed to optimize volumetric efficiency for the engine. Since the expulsion of exhaust gasses is necessary with every combustion cycle, the exhaust system must allow for an unrestricted flow of gasses for maximum engine efficiency. An exhaust leak creates air turbulence in the exhaust piping, and also throws off the volumetric tuning of the exhaust system. Both of these effects lead to diminished engine performance, both in horsepower production and fuel efficiency.

Exhaust Noise

A leak creates excess exhaust noise due to the escaping gasses. This tends to create an air hissing noise audible when in close proximity to the leak location. Additionally, you may experience excess engine noise and/or popping sounds originating from the exhaust leak. While excess noise is undesirable, it has the positive effect of allowing you to easily locate and diagnose exhaust leaks.

Checking for Exhaust Leaks

Exhaust leaks caused by large cracks, rusting and other extensive damage can be diagnosed by visually inspecting the exhaust piping and connections. When checking the exhaust, pay especially close attention to the welding, as these are the most likely locations to crack due to stress and heat. Also, ensure the exhaust hangers are all securely connected to the underside of the vehicle, as loose hangers may allow the exhaust to rattle against the chassis, leading to further damage. Finally, check that the flange bolts securing each piping segment are extremely tight. If you still experience exhaust leaks after inspecting the exhaust system and bolts, replace the exhaust gaskets located at each flange connection.

An air leak in the fuel line of a car means air is getting into the system when there should be a vacuum. This disrupts the air-to-fuel ratio and may result in symptoms like hissing, rough idling or ignition and fuel problems.

Idling

An air leak is most evident when the car is idling, because that is when extra air entering the system can make the most difference. At higher engine speed, air intake rises and extra air is less noticeable, according to the AA1Car website. Idling may be rough or fast.

Leak Points

Whether an engine has fuel injectors or a carburetor, there may also be stalling or misfiring. Common locations of leaks include the gaskets in the intake manifold and the O-rings in the injectors.

Fixes

Methods of detecting air leaks include visual inspection, using an electronic vacuum leak detector or exhaust analyzer. Sometimes, its a simple manner of tightening bolts on the intake manifold or carburetor, but if hoses and parts are worn, they should be replaced.

Older engines and those that suffer under extreme conditions of hot and cold typically manifest oil-leak issues over time. While carbon gaskets are standard parts used to seal between engine parts bolted together, even custom-shaped gaskets dont stop oil leaks 100 percent. Silicone sealant can be used to address these issues on older engine parts. The engine parts already should be taken apart from the engine assembly to prepare for silicone use.

Instructions

1

Pour a gallon or more of fresh kerosene into a plastic bucket or large bin in an area with sufficient air flow. Place the engine parts to be used in the bucket. Let them soak in the kerosene for at least 10 minutes. Pull the parts up one at a time and scrub them with a plastic brush, removing dirt and grime. Rinse the scrubbed part with more kerosene.

2

Take the scrubbed part and lay it out on a flattened cardboard mat to dry out outside. Do not let parts dry indoors. Pour the dirty kerosene back into its original container when finished washing the engine parts.

3

Take the washed parts after they are dry and give them a final wipe with a disposable paper towel. Pay special attention to the mating surfaces of the parts that will join together. Take a plastic scraper or spreader and go along the entire mating surface of an engine part removing any leftover fiber gasket or burnt carbon. Do not use a metal scraper as it will scar the mating surface.

4

Take two matching engine parts and assemble their internals as necessary. Take a tube of high-temperature silicone sealant and spread it carefully along the mating surface of one engine part. Do the same on the second side. Apply the silicone sealant, so it will sandwich between when the engine parts are joined.

5

Position the engine parts, so they can be closed up while the silicone is still wet. Push them together carefully, so the sealant doesnt get twisted or moved wrong. Insert the tightening bolts and nuts. Use a crescent wrench to hold one side of the bolt in place. Tighten each bolt and nut to the proper tightness with a torque wrench and the torque setting specifications for your particular engine. Wipe off the remaining silicone that squeezes off the engine part sides when finished tightening.