Sealing the Engine: Challenger Gaskets and Seals

All of the components in Challengers have machined surfaces. Even when shaped with high precision, a perfect seal is nearly impossible to attain.

Two mating surfaces use a gasket between them to ensure a perfect seal can be attained. Early gaskets were made of paper or quark. Today, these materials are still commonly used but rubbers and metals along with combinations of the materials in layers are used to create a single gasket.

The valve covers of your Challenger live on top of the cylinder head and are responsible for keeping components of the valvetrain safe. The rocker arms, valves, and valves springs (camshafts on Pentastar engines) all live under this cover.

Oil is present in this area and a gasket is used to make a perfect seal between the valve cover and the cylinder head. Molded rubber is usually the material of choice for this gasket on Challengers.

Failure Signs/Causes: Valve cover gaskets will rot, dry, and crack over time. When this happens, a leak will form.

You can identify a valve cover leak when oil begins to seep out. You can visually identify this leak with ease. Another dead giveaway is if oil is reaching the exhaust manifolds and begins to smoke at high temperatures.

The cylinder head and engine block fuse together for the most violent cycle process in the Challenger’s engine. In the combustion chamber, enormous pressures need to be managed during the engine cycle. Water also passes through from the engine block to the cylinder head to keep things cool.

It’s the cylinder head gaskets job to keep pressure from escaping the combustion chamber and water from leaking through the cracks. This gasket is typically constructed from paper, rubber, and metal gaskets.

It’s important to note that the materials used and the thickness of the gaskets will affect compression ratio, and thicker or thinner gaskets can be used here to alter performance.

Failure Signs/Causes: There’s nothing good about a failing cylinder head gasket. When the gasket finally gives up under pressure, coolant may leak into the cylinders and compression may be lost.

Water leaking into the cylinders will contaminate the oil and this can be identified when the oil turns to a milky brown color. If a misfire is present this may also be a direct indication that the cylinder head gasket has failed.

The intake manifold is responsible for transferring air from the throttle body to the cylinder head. This gasket is used to prevent vacuum leaks and ensures the engine receives all the air it needs in order to run properly. These gasket sets usually consist of metal and rubber materials.

Failure Signs/Causes: Intake manifold gaskets will eventually wear over time and may begin to leak. If a leak is present the engine’s running quality will reduce. There are no visual signs to look for other than poor idle quality and throttle response.

The cylinder head is responsible for transporting exhaust from the combustion chamber to the exhaust manifold. The exhaust manifold gasket lives between the cylinder head and the exhaust manifold and is usually made of a metal material. This gaskets job is to seal off any potential exhaust leaks.

Failure Signs/Causes: Exhaust manifold gaskets will begin to wear due to the extreme environment they live in as well as time. The presence of a failed exhaust manifold gasket is easily identifiable by the sound of a ticking coming from the exhaust manifold and a lack in engine performance.

The oil pan lives below the engine block and serves as the engines oil reservoir. The oil pan gasket lives between the oil pan and the engine block. It is responsible for allowing any oil from escaping the pan during the violence of the crankshaft’s counterweights stirring things up. This gasket is comprised of a combination of metal and rubber.

Failure Signs/Causes: The failure of an oil pan gasket will occur over time as the materials deteriorate. The loss of oil can easily be identified by simply looking over the edges of the oil pan where it meets the engine block. 

Replacing gaskets can be a time consuming job when it comes time. In some cases, the failure of one gasket will mean that other gaskets need to be replaced during the repair process.

The cylinder head gaskets failing will mean that the top end of the engine will need to be disassembled. This will mean that the intake manifold, valve cover, and exhaust manifold gaskets will all be removed. Once a gasket is removed it should be replaced.

Whenever a gasket is being replaced you will need to make sure the mating surfaces are as clean as possible to ensure a good seal.