2000 Mazda MX-5 Miata Problems: 7 Known Issues

On the 1999-2005 Mazda MX-5 Miata, the NB Miata (1999-2005) crankshaft position sensor (CPS) is a known failure point. The sensor deteriorates from engine heat, causing intermittent stalling, no-start conditions, and random misfires. Failure is often heat-related - the car runs fine when cold but stalls or dies after reaching operating temperature.

On the 1990-2015 Mazda MX-5 Miata, all generations of Miata (NA through NC) are prone to rear main seal leaks as the engine ages. Oil seeps from the crankshaft rear seal, dripping onto the clutch housing and eventually contaminating the clutch disc. High mileage engines and infrequent oil changes accelerate seal deterioration. This is a labor-intensive repair as the transmission must be removed.

On the 1990-2005 Mazda MX-5 Miata, the 1.6L B6 and 1.8L BP engines use hydraulic lash adjusters inside the bucket followers. Varnish and sludge from extended oil changes, or oil that is too thick or too thin, restrict flow into the adjuster so it cannot stay pumped up. The result is a persistent sewing-machine tick from the top of the engine, loudest on cold start and often not fully quiet once warm. It is frequently misdiagnosed by inexperienced buyers as rod knock, which is a deeper, lower-pitched noise from the bottom end.

On the 1990-2008 Mazda MX-5 Miata, the externally mounted clutch slave cylinder on NA/NB/NC Miatas fails at the piston seal. Fluid weeps past the seal and collects behind the rubber boot, then the cylinder stops holding pressure and the pedal drops to the floor with no gear engagement - frequently without warning. Cars fitted with high-clamp aftermarket pressure plates fail sooner because of the higher pedal pressure, and owners repeatedly report cheap non-Mazda replacement cylinders lasting under a year. The ND uses a different, largely plastic-bodied slave (N251-41-920) that owners also criticize for durability.

On the 1990-2025 Mazda MX-5 Miata, miata soft tops deteriorate over time from UV exposure, flexing during operation, and age. Vinyl tops develop cracks and tears, cloth tops fade and shrink. The rear plastic window (NA) or glass window (NB/NC/ND) can delaminate from the top material, causing water leaks and reduced visibility. Expected soft top life is 7-10 years with proper care.

On the 1994-2000 Mazda MX-5 Miata, the 1994-2000 1.8L BP engines use a wasted-spark coil pack with an integrated igniter transistor. The early version (identified by the 4-pin input connector, later revised to 3-pin) is notorious for internal igniter/solder-joint failure, especially if the ignition is left in the ON position with the engine not running - the igniter transistor overheats and either burns out or melts its own solder connections. The result is a dead cylinder pair, a persistent misfire, and unburned fuel dumped into the catalytic converter.

On the 1999-2005 Mazda MX-5 Miata, nB Miata radiators are prone to failure at the plastic upper tank where it crimps onto the aluminum core. The plastic becomes brittle with age and heat cycling, developing hairline cracks that leak coolant under pressure. This can lead to sudden coolant loss and overheating, especially in spirited driving or hot weather. The OEM radiator typically fails between 80,000-120,000 miles.