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Intake And Exhaust Manifold Gasket Leaks Are Both Bad
All manifold gasket leaks are bad; and as a result can cause all kinds of problems; if not fixed quickly. Intake and exhaust are both bad and do fail quite often.
Let’s Start With The Intake Manifold
So, the intake manifold gaskets are responsible for; sealing the intake manifold against the cylinder head. Apart from sealing engine vacuum; certain designs, will also seal engine coolant. When the intake manifold gasket leaks; it can cause drivability problems and even engine overheating.
Usually a faulty intake manifold gasket will produce a few symptoms; that can alert the driver of a potential issue:
- Engine misfires
- Decreased engine power
- Poor acceleration
- Reduced fuel economy
- Coolant leaks
- Engine overheating
When engines were made of all cast iron; the intake manifold was easier to seal. Consequently, all you needed was simple and relatively inexpensive metal gaskets. But, with the introduction of multiport fuel injection; the intake manifold had to seal more than just the air/fuel mixture. Manifolds became more complex; and plastic became a popular material for casting manifolds; due to its low weight and cost.
But, today is different. Because, on engines with aluminum cylinder heads; corrosion typically erodes the area, around the coolant ports. So, in this case, you can’t blame the manifold gasket leak on the gasket.
Some manufacturers redesigned the intake manifold service gaskets; for some of their problem applications. They’ve changed the sealing beads from silicone rubber; to a tougher material called fluoroelastomer (FKM) rubber. As a result, it is much more resistant to oils; solvents and chemical attack. The original OE gaskets as well as the revised service gaskets; are usually black with orange sealing beads.
When servicing engines; pay close attention to the sealing surfaces; around the coolant ports on the heads. If this area is eroded or pitted; the intake manifold gaskets may not seal properly. Above all, even the smallest leak in a intake manifold; can cause a fuel trim problem. Consequently, finding a leak can be time consuming, using just your eyes and ears.
Furthermore, intake manifold air leaks, will suck in air, not expel it. As a result, what is sucked in will influence the fuel mixture; and impact engine and emissions systems.
A smoke machine allows you to diagnose multiple leaks; in less time compared to other methods. Consequently, a smoke machine can pressurize the intake manifold; and put smoke or vapor into the system. So, if there is a leak; you will see the smoke come out.
So, What About The Exhaust Manifold
The exhaust manifold gasket; as with any gasket; acts as a sealing surface, between two different metal components. The gasket is usually made of layers of metal or composite materials. As a result, preventing leaks as the two metal surfaces go through; countless heating/cooling expansion and contraction cycles.
Generally, exhaust manifold gaskets are hardy items; often lasting well over 100,000 miles. A lack of engine maintenance and carbon buildup, however; can cause hot spots in the combustion chambers and exhaust ports. This can cause a gasket; to catch fire or expand outward. This is a good reminder to use fuel system cleaners; to remove carbon buildup.
So, a failed gasket also allows fresh air into the exhaust system; at a point it wasn’t designed for. As a result, it is not uncommon to end up with burned exhaust valves.
When exhaust manifold leaks happen; the symptoms are rather obvious:
- Increased engine noise
- Smells or visible exhaust emissions
- Loss of performance
- Excessive fuel consumption
So, exhaust gas typically flows through the exhaust manifold; catalytic converter, resonator and finally the muffler; which connects to the tailpipe. Therefore, each of these parts needs to function properly; for the system to work.
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