Manifold Gasket Leaks - Intake And Exhaust, Are Both Bad

All manifold gasket leaks are bad and as a result, can cause all kinds of problems.

So, intake and exhaust leaks are both bad, and actually do fail quite often.

But, intake manifold gasket leaks, are worse than exhaust. Because, they have more of an effect, on how your engine runs and, can do way more damage.

Everything coming in and going out of your engine, is affected by, manifold gasket leaks.

Exhaust Manifold

Generally, exhaust manifold gaskets are hardy items, often lasting well over 100,000 miles. But, a lack of engine maintenance and carbon buildup, can cause hot spots. Usually, in the combustion chambers and exhaust ports. This can cause a gasket to, catch fire or expand outward.

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 unusual to end up with, burned exhaust valves.

When exhaust manifold gasket leaks happen, the symptoms are rather obvious:

Increased engine noise.
Smells or visible exhaust emissions.
Loss of performance.
Increased fuel use.

Intake Manifold

When engines were made of all cast iron, the intake manifold, was easier to seal. Consequently, all you needed was, simple and relatively cheap metal gaskets. But, with the introduction of multiport fuel injection things changed. Consequently, 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. Mostly due to its low weight and cost.

Apart from sealing engine vacuum, certain designs, will also seal, engine coolant. So, when the intake manifold gasket leaks, it can cause drivability problems and even engine overheating.