Exhaust Flange Gaskets

Is exhaust gas leaking at the downpipe, or is there a ticking sound from the joint after the turbo? It may be caused by a leaking gasket. This category gathers flange gaskets for joints between the turbo, downpipe, up-pipe, exhaust manifold and collector – for both repairs and tuning projects.

What a flange gasket does

The gasket seals the joint between two exhaust components, e.g. between the turbo and downpipe or between the exhaust manifold and up-pipe. It has to withstand high temperatures, vibration and the expansion of the metal as it heats up and cools down. A leaking joint can cause a ticking sound, soot around the flange and affect the readings from a nearby lambda sensor.

How to choose the right gasket

Start with the flange shape, pipe diameter and bolt pattern – the number and position of the bolts must match your specific joint. After that, it comes down to material:

• MLS – multiple layers of steel, e.g. the BLOX Racing 6-layer MLS gasket for Subaru EJ20/EJ25.
• Single-layer stainless steel – e.g. Cometic Gasket .016 in for four-bolt K03/K04 turbo outlets.
• Replacement gaskets for the exhaust pipe flange – e.g. from Fel-Pro for models including Subaru WRX and Honda Civic.

Choose based on temperature, power goals and the condition of the flange rather than thickness alone, and always check the part number against your car and engine.

Installation and adjacent joints

Clean the surfaces of old residue and check that they are neither warped nor cracked. Tighten the bolts evenly according to the manufacturer's instructions. The category also includes brands such as GrimmSpeed, JBA and Magnaflow. If you need to seal the manifold itself or the turbo inlet, you will find exhaust manifold gaskets and turbo gaskets under exhaust gaskets and seals.

Frequently asked questions

Can I reuse an exhaust flange gasket?

It is typically not recommended. MLS and steel gaskets are compressed on first tightening and often seal less well the second time. If the joint has been taken apart, a new gasket is the safest route to a tight seal.

What is the difference between an MLS gasket and a single-layer steel gasket?

An MLS gasket consists of several steel layers, which can provide a little spring and better sealing against small irregularities. A single-layer gasket is thinner. The choice depends on the condition of the flange, temperature and the manufacturer's recommendation.

Why is the exhaust still ticking after a gasket replacement?

It may be caused by warped or cracked flange surfaces, loose or stretched bolts, a gasket that doesn't match the bolt pattern, or a leak elsewhere, e.g. at the manifold. Check the surfaces and tightening first.