1998-2005 · 1.8L BP-4W/BP-VE/BP-Z3 petrol (140-146 hp)
The second-generation Miata is a legendary affordable sports car with a simple, reliable engine and huge aftermarket support. The 1.8L four-cylinder is bulletproof when maintained. Main concern is rust in rocker panels, wheel arches, and front frame rails – inspect thoroughly before purchase. Timing belt (not chain) requires replacement every 60,000 km. Soft top degrades with age. Non-interference engine means a snapped belt won't destroy valves. Parts are cheap and widely available. Manual gearbox is robust; avoid high-mileage examples without service history.
Rust in rocker panels and wheel arches€900 - €4,000
Rust from inside out - by the time it's visible externally, structural damage is extensive · more· less
This is the MX-5's biggest enemy. Rocker panels (sills) and wheel arches rust from the inside due to blocked drain holes, salt, and moisture trapped in seams. NB models are also prone to front frame rail rust. By the time paint bubbles appear, the inner structure is likely compromised. Repair costs vary: €450-500 per side for minor underside rust, €1,000+ per side if inner sills need replacing. Severe cases requiring full rocker and quarter panel replacement can reach €3,000-7,000. Check thoroughly – lift carpet, inspect with flashlight, poke suspected areas gently. Cars stored outside or driven in winter salt are highest risk.
Soft top deterioration€420 - €1,150
Vinyl degrades with UV, rain rails crack, causing water leaks into cabin and trunk · more· less
The vinyl soft top breaks down at stress points, especially around the rear window. Rain rails crack and allow water to pool in the rear deck, accelerating rust. Check zipper operation (if equipped), inspect plastic window for brown spots (early sign of failure), and test for leaks. Budget vinyl replacement: €420 (parts only) to €725 fitted. Premium mohair with glass window: €1,150+ fitted. DIY-friendly if you're handy. Keep drain tubes clear to prevent water damage.
Timing belt failure€600 - €900
Must replace every 60,000 km or 10 years – good news: non-interference engine · more· less
NA and NB use timing belts, not chains. Replace every 60,000-90,000 km maximum or every 10 years regardless of mileage. If it snaps, the engine simply stops – the BP engine is non-interference, so no valve/piston collision damage. Professional replacement costs €600-900 including water pump, tensioner, and seals (highly recommended to do all together). Always replace the water pump simultaneously since it's behind the belt. Missing service history? Assume belt is due immediately.
Water pump and thermostat failure€600 - €950
Water pump behind timing belt, often done together; thermostat failure causes overheating · more· less
Water pump is located behind the timing belt, so 90% of labor overlaps with belt service. Typical lifespan 70,000-100,000 km. Symptoms: coolant warning light, overheating, poor cabin heat. Always replace pump when doing timing belt. DIY parts cost €60-155 for pump kit. Thermostat can stick, causing overheating or poor warm-up. Often replaced preventatively during water pump service (adds €15-40 in parts).
Radiator cracking (plastic end tanks)€550 - €1,450
Plastic end tanks become brittle, crack over time, spitting coolant and causing overheating · more· less
Common NB issue: the top plastic radiator tank cracks and leaks coolant. When pressurized system loses integrity, overheating occurs rapidly. White smoke under hood is a telltale sign. Left unaddressed, overheating can warp the head or blow the gasket. Professional replacement: €550-1,450. Always replace thermostat and flush system when replacing radiator. Check coolant level regularly and look for green/pink puddles under car.
Crankshaft pulley wobble€300 - €1,200
Woodruff key wears, pulley wobbles – check at cold idle with hood open · more· less
The crankshaft pulley can develop wobble due to worn woodruff key or keyway damage. Check at idle with hood open – visible wobble is a problem. Minor wobble at 800 rpm that disappears above 1,200 rpm may be acceptable. Repair involves new crank bolt, gear, woodruff key, and Loctite. Since pulley must come off, do timing belt, water pump, and front main seal simultaneously. Severe keyway damage may require machining or engine swap. Early diagnosis is key – severe wobble can throw belts.
Clutch slave cylinder failure€100 - €300
Leaking slave makes shifting impossible; common on 1990-2008 models · more· less
The clutch slave cylinder can leak fluid, making gear engagement impossible. Common failure point on Miatas driven hard or over 10 years old without replacement. Professional replacement: €250-290. DIY parts: €30 (OEM quality). Always consider replacing the master cylinder simultaneously if slave fails, as it indicates overall hydraulic system age. Symptoms: soft clutch pedal, difficulty shifting, fluid leak near transmission bell housing.
Shock absorber wear€475 - €1,050
Replace every ~55,000 km; collapsed top mounts cause harsh ride over bumps · more· less
Miatas use traditional spring-and-shock suspension. Springs rarely fail, but shocks, mounts, and bump stops wear. Collapsed upper mounts (top hats) cause the car to crash over small bumps. Replace shocks every 35,000-55,000 km for best ride quality. Professional replacement: €475-1,050 for a pair. Always replace in pairs (both front or both rear). Aftermarket options like Bilstein available. Signs: bouncy ride, excessive body roll, fluid leaking from shock body, uneven tire wear.
Cam Angle Sensor (CAS) oil leak€50 - €150
Most common Miata oil leak; drips down back of engine onto transmission · more· less
The CAS O-ring is the #1 cause of MX-5 oil leaks. Located at rear of engine, oil drips onto transmission, making diagnosis difficult from below. Very common, especially after timing adjustment. DIY repair: €2-10 and 10-20 minutes with basic tools (10mm socket, 12mm wrench). O-ring part: FEL-PRO #35608. Professional repair: €50-150 (mostly labor). Often done alongside valve cover gasket since valve cover removal makes CAS access easier. Not a serious issue but messy and can hide other leaks.
Valve cover gasket leak€130 - €255
Oil leaks from under valve cover, potential fire risk if severe; easy DIY · more· less
Valve cover gasket hardens with age and heat cycles, causing oil to seep down the engine side. Worst case: oil drips onto exhaust manifold, creating fire risk and burning oil smell. Professional replacement: €130-255. DIY-friendly repair – gasket costs €10-25, takes 1-2 hours. Symptoms: oil visible on engine exterior, burning oil smell, oil-soaked spark plug wells (causes misfires). Replace spark plug tube seals simultaneously. Always use oil-resistant RTV sealant where specified.
Fuel pump failure€640 - €1,300
Intermittent fuel delivery, hesitation under load, whirring noise from tank · more· less
Fuel pumps can fail gradually or suddenly. Symptoms: engine hesitation/surging under load (accelerating, hills), difficulty starting, whirring noise from rear. Turn key to ON (not cranking) – you should hear 2-5 second whirring. Silence indicates electrical issue or dead pump. Professional replacement: €640-1,300. DIY parts: €80-200 for pump. NB has trunk access plate above tank, making replacement easier than many cars. Prevent premature failure: avoid running tank below 1/4 full (fuel cools/lubricates pump), replace fuel filter every 50,000 km.
Alternator failure€600 - €735
Battery warning light, electrical issues, grinding noise; NB has grounding issues · more· less
Alternators typically last 80,000-150,000 km. NB-specific issue: poor alternator grounding can cause voltage runaway (20V+), damaging ECU. Symptoms: battery light while driving, dim/flickering lights, hard starting, grinding bearing noise. Test: engine running, headlights/blower on – voltage should be 13.5-14.5V. Below 13.8V indicates failure. Professional replacement: €600-735. DIY prevention: grind paint off alternator case, install proper ground strap to block. Takes 10 minutes, costs €5, prevents expensive damage.
PCV valve regulates crankcase pressure. When clogged with oil residue, it causes excess smoke, rough idle, oil consumption, and pressure buildup that can blow gaskets/seals. Test: remove oil cap while engine idles – engine should stumble slightly (vacuum leak). If it surges heavily or if a rubber glove/plastic wrap inflates/blows off valve cover, PCV is faulty. Easy fix: clean with brake cleaner, shake to hear ball bearing rattle. Replace if cleaning doesn't help. Genuine part: €10-30. Rarely fails completely, just gets gummy. Check during oil changes.
Reliable sports car with affordable maintenance
The NB MX-5 is one of the most reliable and affordable sports cars you can own. The 1.8L engine is bulletproof with proper maintenance. Most issues are age-related (rust, rubber degradation) rather than mechanical failures. Parts are cheap and widely available. The enthusiast community provides excellent DIY support. Rust is the only serious concern – inspect thoroughly before buying and maintain drain holes religiously.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete records essential, especially timing belt replacement. Verify last belt change date and mileage.
Tires
Check tread depth (minimum 3mm), manufacture date codes (replace if over 6 years old), uneven wear patterns.
Cold start
Engine must be completely cold. Listen for unusual noises, check for smooth idle, white/blue smoke.
Test drive minimum 20 minutes
Include varied speeds, sharp turns, aggressive acceleration. Feel for vibrations, pulling, strange noises.
Underbody inspection
Use flashlight to inspect underneath. Look for fresh undercoating (may hide rust), leaks, damage.
Specific for this vehicle
Rust inspection is critical
Inspect rocker panels thoroughly – lift carpet inside car, look for paint bubbles, poke gently with screwdriver (gently!). Check wheel arches front and rear, inside and out. Inspect front frame rails from underneath. Look in trunk for water stains. If seller refuses underbody inspection, walk away.
Check crankshaft pulley wobble
With hood open and engine at cold idle, visually inspect crank pulley (lowest pulley on front of engine). Any visible wobble is a red flag. Small wobble only at idle that disappears above 1,200 rpm may be acceptable but budget for repair.
Verify timing belt service history
Belt must be replaced every 60,000 km or 10 years maximum. No service records? Assume it's due immediately and factor €600-900 into purchase price. Check for water pump replacement at same time.
Soft top condition
Test zipper operation (if equipped). Check plastic rear window for brown spots, cracks, or opacity. Close top and spray with hose – check for leaks inside cabin and trunk. Inspect rain rails for cracks. Test drain holes by pouring water into soft top channels behind seats – should drain out bottom of car, not into interior.
Clear drain holes and check for blockage
Pour water into soft top drain channels and hood drains (behind seat belt towers). Water should exit cleanly under car within seconds. Blocked drains = guaranteed rust. Check for water stains in trunk and under carpet.
PCV valve check
With engine idling, remove oil filler cap. Engine should stumble slightly. Place rubber glove or plastic wrap over valve cover opening – it should have gentle suction, not inflate forcefully. If glove inflates/blows off, PCV valve is clogged (minor issue, easy fix).
Check for oil leaks
Inspect rear of engine for CAS O-ring leak (very common, cheap fix). Check valve cover perimeter for seepage. Look under car for drips on transmission bell housing (slave cylinder), oil pan, front crank seal. Small leaks are normal on 20+ year old cars but factor into negotiation.
Coolant system inspection
With engine cold, check coolant level and color (should be green/pink, not brown or milky). Inspect radiator plastic end tanks for cracks. Check hoses for bulges, cracks, or soft spots. Look for white crusty deposits (leak evidence). Pressure test recommended.
Manual gearbox operation
Test all gears including reverse. Listen for grinding, whining, or difficulty engaging. Synchros can wear – second gear is most common. Clutch should engage smoothly without judder. Pedal should feel firm, not spongy (slave cylinder issue if spongy).
Suspension and alignment
Drive over speed bumps and rough roads. Car should absorb bumps without crashing or bouncing excessively. Collapsed top mounts make car feel harsh. Check for pulling to one side. Inspect shock absorbers for oil leaks. Uneven tire wear indicates alignment or suspension issues.
Check recall status using VIN at official Mazda website or dealer. The 1999 model year had the most NHTSA complaints (75 total), including valve cover gasket issues. TSB database available at miata.net/garage/tsb/ for comprehensive list. Most NB issues are age-related rather than factory defects.
Warranty Status
Factory warranty (3 years / 100,000 km)Expired on all NBs
Extended warranty availabilityLimited for 20+ year old cars
All NB MX-5s (1998-2005) are well outside their original factory warranty. Third-party extended warranties are rare and expensive for cars this old. Budget for repairs yourself. The good news: parts are cheap, labor is straightforward, and the enthusiast community provides excellent DIY support. Many repairs can be done at home with basic tools.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.