ND Rear Exhaust "Donut" Gasket

DESCRIPTION

Replacement factory Mazda "donut" style gasket for the junction between OEM midpipe and OEM muffler (or any RoadsterSport muffler) on all 2016 and newer MX5. These live a hard life on the ND Miata as Mazda made it a flex joint with one flat side and one rounded side and springs in the connection so that as the muffler moves around on the rubber hangers it grinds against the gasket and is held there by just spring tension. Over time all that grinding slowly wears away the gasket and it gets thinner and less effective.

If you have a leak at this junction when you change to an aftermarket muffler, likely this gasket is just too worn away from sporty driving fun. Changing to a fresh gasket as sold here usually solves the leak.

If you have over 20k miles on your ND, this is a good addition to your new muffler purchase.

Note this will not stop condensation weep at this joint. It's a moving joint, metal on one side, condensation passing through that sort of flex joint is going to happen and we see it on these cars brand new from the dealership. But if you feel 'puff puff puff' actual exhaust gases leaking then consider a replacement. Another trick is to increase spring tension with a few washers between nuts and the springs to 'push' the gasket a little harder into the mouth of the muffler side receiver.

Brian's Notes: Think of this graphite impregnated gasket as much like a number 2 pencil, as the round side of it rubs into the new home in the 'mouth' of the muffler it builds a transfer layer. The springs push the gasket into that muffler mouth as you drive. The engine wags and wags and wags the gasket back and forth in hundreds of little micro movements per mile. That process builds up more and more of the graphite as a transfer layer in the mouth of the muffler, improving sealing with some miles through the first year. And that also means the sealing will peak and then the material eventually wears down and will seal less and less after a few years. This style of gasket never gets water tight, it will always drip condensation at that joint, but in the first year after install it will seal better and better with some miles as the transfer layer is built up.