Infiniti M35h Exhaust Manifold Replacement Cost
How Much Does an Exhaust Manifold Replacement Cost?
Exhaust Manifold Replacement Service and Cost
The exhaust manifold is located between the engine cylinder head and catalytic converter. The purpose of this manifold is to collect exhaust gas as it leaves the cylinder head.
As the engine pumps hot exhaust gases out of the cylinder head, the exhaust manifold receives it, and pressure builds inside the manifold. The metal gasket expands with the cylinder head and manifold, to fill the tiny gap between them, so back pressure may build without the gas escaping the exhaust system,
When the exhaust manifold becomes corroded to the point of failure, the result will be a tapping noise from a crack in the exhaust manifold. If the muffler bracket has broken, or the rubber hanger is worn, the muffler and exhaust pipe may hang down, placing additional strain on the hot manifold, and cause the exhaust manifold gasket to leak. Lastly, leaking from the exhaust manifold could register a lean fuel condition at the oxygen sensors, causing black smoke from the exhaust under heavy acceleration, check engine light illumination, and OBD trouble codes for exhaust and emissions, fuel delivery, and lean running conditions.
Driving a vehicle with a leak in the exhaust manifold is generally not recommended for very long. It can ruin fuel mileage, fail a smog inspection, ruin the catalytic converter, and cause damage to exhaust valves.
Normally, the exhaust manifold can go thousands of heat cycles before failure, but engine condition, and driving style may play a significant role in longevity, except for in cases of corrosion, and collisions. Most exhaust manifolds last the lifetime of the engine, and beyond. However, since the rate of decay is dependent on the operating environment, the likelihood of replacement is based on age, rather than mileage. Lastly, hot engine temperatures from improper air fuel ratios will cause leaks in cast manifolds at any mileage.
Exhaust Manifold Replacement Repair Information
Identifying an exhaust manifold leak can be very easy if ticking is present, and plenty of exhaust gas is making a stink at the engine, but minor leaks can be tricky. Ordinarily, the vehicle will be raised, and the exhaust manifold will be inspected for signs of leakage, such as black marks, and burned non-metallic components around the exhaust manifold. If there are no signs, the exhaust may be smoke tested, or plugged to make leaks more apparent.
Exhaust manifold and gasket replacement only requires the manifold retaining hardware to be removed, the old gasket removed, and all mating surfaces cleaned thoroughly. If the manufacturer specifies sealant, it is applied to the gasket, otherwise the gasket is placed on the exhaust studs. The exhaust manifold will slide in place on the gasket, and the technician will torque new exhaust manifold retaining fasteners to factory specification.
As manufacturers spend millions of dollars designing the perfect exhaust system for their engines, we recommend using at least OEM quality parts, if not parts from the OEM.
The exhaust system operates at extreme temperatures, so metal becomes brittle after a long service life. Fasteners need to be replaced when an exhaust manifold gasket is replaced as the old bolts are unreliable, and the fasteners may be destroyed during removal.
Replacing an exhaust manifold and gasket is only a DIY capable project if the leak can be positively diagnosed at home, and when caught early. If caught late, the exhaust valves must be inspected by a trained professional technician. If any welding is required, a professional exhaust welder should complete the repair.
Most Common Infiniti M35h Repairs
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