Intake Manifold Gaskets

Is your idle rough because of a vacuum leak, or have you taken the intake manifold apart? An intake gasket seals between the cylinder head and the manifold, and we stock standard gaskets, thermal gaskets and gasket sets for repairs and projects.

What does an intake gasket do?

The gasket seals the joint between the cylinder head and the intake manifold so the engine doesn't draw in air that bypasses the measurement the engine management uses to calculate the mixture. A leaking gasket can cause a rough idle, a lean mixture and fault codes, and on boosted engines the joint can also leak under load. On some engines coolant passages run through the joint, so a failed gasket there can also cause coolant loss.

How to choose an intake gasket

• Port shape and size: The gasket must match both the cylinder head and the manifold. There are, for example, versions for small port heads, and a gasket that protrudes into the port can disrupt airflow.
• Material: Thermal gaskets, e.g. from Torque Solution and BLOX Racing, can reduce heat transfer from the cylinder head to the manifold and thus keep the intake air cooler. The effect depends on engine, manifold and driving.
• Single gasket or set: Fel-Pro, for example, offers intake gasket sets, which is practical if several joints need to be taken apart. The category also includes Edelbrock and Cometic Gasket.

Installation and maintenance

Clean both surfaces thoroughly and don't reuse the old gasket. Tighten the manifold to the vehicle manufacturer's torque and sequence, and check for vacuum leaks after installation. If the cylinder head is coming off anyway, it's worth looking at head gaskets or a complete engine gasket set. Other gaskets are found under engine gaskets and seals.

Frequently asked questions

How can I tell if the intake gasket is leaking?

Typical signs are a rough idle, a hissing sound, lean mixture fault codes and high fuel trims. If the engine has coolant passages through the joint, coolant loss can also be caused by the gasket. A smoke test of the intake can show where the leak is.

What is the difference between a thermal and a standard intake gasket?

A thermal gasket is designed to insulate the manifold from the heat of the cylinder head, so the intake air is typically kept cooler. How much it matters depends on engine, manifold and driving, and the gasket must still match the ports precisely.

Can I reuse the gasket once the manifold has been off?

It's not recommended. The gasket compresses when it's tightened and rarely seals as well again. Replace it every time the manifold is removed, and at the same time check that the surfaces are clean and flat.