Primo Replacement Gasket for Oval X-Large 400, Large 300

Which Primo grills does this gasket fit?

The Oval X-Large 400 and the Oval Large 300, as named in the listing. Smaller Primos take a different seal, so a Junior owner should order the Primo replacement gasket for the Oval Junior 200 instead. Match the gasket to your grill's model rather than assuming that a seal from one oval will run correctly around the rim of another.

How do I know when my gasket needs replacing?

The clearest sign is a grill that will not hold a low temperature any more, especially one that used to. Look also at the seal itself with the dome open: thinning, flattened, missing or charred stretches all mean it is no longer meeting the other half properly. A dome that closes with a visible gap is the same story.

How do I fit a new gasket?

Work on a cold grill. Open the dome, take off the old seal, and clean every trace of it and its residue from both rims, because anything left behind stops the new one sitting flat. Lay the new gasket evenly around the rim without stretching it, then close the dome and leave it shut so it settles against the other half.

Does the same gasket fit the Oval XX-Large?

Go by the listing, which names the X-Large 400 and the Large 300. Those are the fits to rely on. Kamado seals follow the rim they run around, so buying a gasket because the grill looks a similar size is a good way to end up with one that does not sit right and leaks anyway.

Should I do the gasket at the same time as the hinge hardware?

It is a sensible pairing. Both rims are easy to reach when the bands are loose, and both parts wear over a similar span, so if your grill is old enough to want one it is often old enough to want the other. Doing them together also means you only realign the dome once.