1990 MAZDA MX-5 MIATA

Typical onset: 80,000-150,000 mi

Symptoms: oil dripping from timing belt cover area, oil spray on underside of hood, oil coating timing belt

Fix: Replace crank seal and cam seals while timing belt is off. 3-4 hours labor if doing belt/water pump/seals together as preventive maintenance, which you should.

Estimated cost: $600-900

Typical onset: 60,000+ mi

Symptoms: oil smell in cabin with heat on, oil pooling on exhaust side of head, visible seepage around cam angle sensor

Fix: Valve cover gasket, half-moon seals, and CAS O-ring replacement. Easy DIY, 1.5 hours labor. Use OEM Mazda gaskets, not cheap cork.

Estimated cost: $200-350

Symptoms: sudden loss of power, grinding/rattling from front of engine, no-start after driving normally, timing marks off despite new belt

Fix: The short-nose crank (1990-early 1991) can shear the woodruff key if crank bolt loosens or was overtorqued. If key shears, crank and timing gear are toast. Requires engine removal, crank replacement or machine work, plus new timing components. 12-18 hours labor minimum if crank is salvageable, full rebuild if not.

Estimated cost: $2,500-5,000

Typical onset: 100,000+ mi

Symptoms: ticking/tapping from valve cover on cold start, noise persists or worsens after warmup, improves slightly with high-quality oil

Fix: Hydraulic lash adjusters wear or get clogged. Not dangerous, but annoying. Replacement requires cam removal: 6-8 hours labor. Many owners live with it. Use 10W-30 synthetic and Mazda oil filters to minimize.

Estimated cost: $800-1,200

Typical onset: All survivors at this age

Symptoms: coolant leaks from plastic radiator end tanks, overheating in traffic or summer heat, radiator cap fails to hold pressure, heater core leaks into passenger footwell

Fix: Original radiators are 30+ years old and fail catastrophically. Replace radiator, hoses, thermostat, and cap as a package. 2-3 hours labor. Aftermarket aluminum radiators are popular and work well.

Estimated cost: $400-700

Typical onset: 80,000-150,000 mi

Symptoms: clunking on hard acceleration or deceleration, excessive drivetrain movement, shifter vibration, difficulty getting into gear

Fix: The aluminum PPF can crack, especially on lowered or hard-driven cars. The rubber mounts also disintegrate. Replacement involves dropping exhaust and unbolting PPF; 2-3 hours labor. Upgraded polyurethane mounts reduce future failures but add NVH.

Estimated cost: $300-600

Symptoms: hard starting after sitting, fuel smell in trunk area, rust flakes in fuel filter, rough idle or hesitation, fuel gauge erratic or inoperative

Fix: Cars stored outdoors or in humid climates develop internal tank rust. Fuel pump/sender units fail. Filter clogging is common. Tank removal and cleaning or replacement: 4-6 hours labor. Pump/sender unit adds 1-2 hours if separate.

Estimated cost: $600-1,200