I checked the condition of the spark plugs today. When I put one of the spark plugs back in, a round bit of rubber came out with the socket, looks like a seal, although I’m assuming it’s part of the rocker cover gasket. The spark plug threads were also quite greasy, which I assumed was antiseize, but I’m now worried is oil…
Is this a big issue? The car seems to run great and really pulls in all gears. It takes a little longer to start than I’m used to but I’m not sure if that’s just an MX5 thing (or maybe a bad battery/starter/etc).
There is a round piece of the cam cover gasket around each plughole but I can’t see how it could possibly have come away. It sits in an insert in the cam cover so I would say impossible for it to appear in the plughole.
If it has gone you would have a plug well full of oil. Sounds like you have a small amount of grease on the plugs not teaspoons of oil so I doubt there is a problem.
Perhaps the cam cover gasket was changed before and this piece has broken off a previous gasket?
In any event if you do decide to change the gasket use a genuine Mazda one if you wish to avoid problems.