Parts for your 2018 Honda Odyssey-Exhaust gasket

2018 Honda Odyssey exhaust gasket — what it does and when to replace it

Based on Honda Service Information for the 2018 Odyssey (Exhaust System procedures in the service manual) and genuine Honda parts catalogues for the J35-series V6, this model absolutely uses exhaust gaskets. They’re specified at key joints: the exhaust manifold-to-cylinder head, and the flanged or “donut” gasket joints between the front pipe, catalytic converter, and the rest of the system. So an exhaust gasket is relevant and fitted to the 2018 Honda Odyssey.

The exhaust gasket’s job is simple but crucial: seal hot exhaust gases so they exit through the system, not into the engine bay or underbody. On the Odyssey’s V6, manifold gaskets keep the seal at the head, while ring/donut gaskets and flat flange gaskets maintain a gas-tight joint further down the pipes. Good sealing prevents that sharp ticking on cold start, keeps fumes out of the cabin, protects oxygen sensor readings, and helps the V6 run smoothly with the right backpressure.

There’s no fixed replacement interval, but best practice is to fit new gaskets any time a joint is separated—manifold off for repairs, catalytic converter replacement, or exhaust section swaps. They’re cheap insurance against leaks.

• Typical leak clues: a tapping or puffing noise (worse when cold), sooty marks at a joint, whiffs of exhaust under load, or fuel economy drop from skewed O2 readings.
• Inspection tip: at regular servicing or every 60,000 km, have a look and listen under the vehicle, in NZ WOF or Aussie roadworthy checks, any exhaust leak can trigger a fail.

Replacement pointers a technician will follow on the Odyssey:

• Use OEM-quality multi-layer steel manifold gaskets and correct-size ring/donut gaskets for flanges. Replace spring bolts and studs if corroded.
• Clean mating faces and check for warping or pitting, even a small nick can cause a hiss under load.
• Torque fasteners evenly in the specified sequence (centre-out on manifolds) to the service manual spec, recheck after a heat cycle if dictated by procedure.
• Let the system cool fully, penetrating oil on old hardware saves snapped studs.

If there’s a persistent smell of exhaust, a louder note than usual, or a CEL after recent exhaust work, don’t ignore it—carbon monoxide is no joke. A fresh gasket and correct torque usually sorts it fast, and keeps the family hauler quiet and compliant.

Popular questions

Does the 2018 Honda Odyssey have exhaust gaskets and where are they located?
Yes. The Odyssey uses manifold gaskets between the cylinder heads and exhaust manifolds, plus gasketed joints (flat flange or donut style) at the front pipe, catalytic converter interfaces, and further down the system where sections bolt together.

What are the signs of a bad exhaust gasket on a 2018 Odyssey?
Common signs include a ticking or puffing sound on cold start, a sharp exhaust note under acceleration, soot around a joint, a slight exhaust odour near the front of the vehicle, and sometimes poor fuel economy from disturbed O2 sensor readings.

Should gaskets be replaced when fitting a new catalytic converter or exhaust section?
Absolutely. Once a joint is separated, the old gasket may not reseal reliably. Fit new gaskets and any specified spring bolts or studs, clean the mating faces, and torque to spec for a quiet, leak-free result.