Your stock overflow tank is nasty yellow plastic. This one is sexy cool aluminum, so it's not going to crack with high heat - and the stock tank in a 1990 Miata is over 30 years old by this point. There's always the risk it will crack on track.
We ran into a small issue with this batch of NA tanks, though - these will just contact the charcoal canister. 100% perfect parts are on their way (no ETA at this point), but we've devised a small 3D-printed bracket to move the charcoal canister over slightly and create the necessary clearance. We've discounted them to account for that, but they're perfect otherwise.
Includes a sight tube so you can confirm your coolant level.
Exclusive to FM!
Fits NA Miatas.








