How to Replace an Exhaust Manifold Gasket

exhaust pipes on the back of a red car
  • 1-2 hours
  • Intermediate
  • 0-100
What You'll Need
Wrench set
Socket set
Putty knife
Header gaskets

Also known as a donut, an exhaust Manifold gasket seals the area where the exhaust pipe is attached to manifolds made out of cast iron on custom and performance vehicles to reduce weight and increase the car's performance. Older vehicles use asbestos gaskets, so those concerned about health and safety need to replace their old ones with new, high-quality gaskets. It is very easy to change an exhaust manifold gasket with the use of a few tools.

Step 1 - Locate the Bolts

view of exhaust system under a car

Jack up your car, secure with jack-stands, and roll under it. There are eight bolts that secure the exhaust flange. There are two located on each exhaust port that is located on both sides of the header tubes.

Step 2 - Loosen the Bolts

Once you have located the bolts, you will need to loosen all of them. You should only remove the six inboard retaining bolts. The two that you should leave are the ones that are on the left and right sides of the header.

Step 3 - Loosen the Exhaust Flange Gasket

With a putty knife, loosen the exhaust manifold from the head. It will be stuck on either the left or right side, although sometimes it can be stuck on both ends. To loosen it, slide the knife under the manifold and move it back and forth gently until you feel the exhaust manifold gasket wiggling.

Step 4 - Remove the Exhaust Flange Gasket

Remove the old exhaust manifold gasket that is located between the head and the header flange. Check to see if there are any broken parts of the gasket. If there are, it means that there is a piece of gasket still stuck to either the manifold or the head. If this is the case, you need to remove the gasket bits that are stuck there or remove the remaining bolts. If the bits are not removed, the new exhaust flange gasket will not seal properly. Take your putty knife and gently scrape around the area where the exhaust flange was previously attached. Scrape off bits and pieces of the old exhaust manifold gasket. Continue in this fashion until you feel satisfied that all old pieces have been removed.

Step 5 - Install the New Exhaust Manifold Gasket

Installing exhaust flange

To install the new exhaust manifold gasket, insert it into the area between the head and the manifold. You will need to slot it over each end in order for it to slide over the bolts that were left on the head in order to properly align the gasket. Put back the six bolts that you took out in step 2, and ensure that they go through the header gasket's holes. Only tighten them when all of the bolts are in place before pulling down the manifold across the head. You can then proceed to the engine's other side and repeat the above steps.

A little grease and a muscle are all you need for a faster, more efficient power machine.