1992 MAZDA COSMO

Typical onset: 60,000-100,000 mi

Symptoms: Hard starting when engine is hot, Loss of power and poor fuel economy, White or blue smoke on startup, Rough idle and misfires under load

Fix: Full rotary rebuild: disassemble engine, replace apex seals, side seals, corner seals, resurface rotor housings or replace if worn beyond spec. 20B rebuild is 25-35 hours labor; 13B-RE is 18-25 hours. Parts scarce—often sourced from Japan or specialty rotary shops.

Estimated cost: $4,500-8,500

Typical onset: 70,000-120,000 mi

Symptoms: Transmission slipping or delayed engagement, Pink milky fluid in transmission pan, Overheating transmission during highway driving, Coolant loss with no visible external leaks

Fix: Replace corroded oil cooler lines and flush transmission completely—old fluid mixed with coolant destroys clutch packs. If contamination went unnoticed, internal transmission damage requires rebuild. Cooler line replacement is 3-4 hours; full flush adds 2 hours. Transmission rebuild if damaged: 12-18 hours.

Estimated cost: $800-1,200 for lines and flush; $3,000-5,000 if rebuild needed

Typical onset: 50,000-90,000 mi

Symptoms: Overheating in traffic or under boost, Coolant leaks from front of engine, Temperature gauge swings erratically, Steam from hood after shutdowns

Fix: Rotaries run hotter than piston engines and punish cooling components. Replace water pump, thermostat, all rubber hoses, and flush system with proper pre-mix coolant. 20B has more complex plumbing than 13B. 6-9 hours labor depending on accessibility and turbo removal.

Estimated cost: $1,200-2,200

Typical onset: 80,000-130,000 mi

Symptoms: Loss of boost pressure or surging under throttle, Excessive blue smoke from exhaust, Loud whining or grinding noise on acceleration, Oil leaks around turbo manifold

Fix: Sequential turbo system uses primary and secondary turbos with vacuum-controlled switchover—seals fail, bearings wear, actuators stick. Rebuild or replace both turbos. Removal requires exhaust manifold work and coolant drain. 12-16 hours labor. OEM turbos unavailable—use remanufactured or aftermarket.

Estimated cost: $2,500-4,500

Typical onset: 60,000-110,000 mi

Symptoms: Fuel smell in cabin or engine bay, Rough idle and hesitation under load, Hard starting after sitting overnight, Visible fuel weeping at injector bases

Fix: Rotaries use large-capacity injectors that develop seal leaks or clog from carbon buildup. Remove fuel rail, replace all injector o-rings and seals, ultrasonic clean or replace injectors. 4-6 hours labor. Clean injectors often preferred due to parts scarcity.

Estimated cost: $600-1,200

Typical onset: 60,000-100,000 mi

Symptoms: Clunking noise during shifts or acceleration, Excessive drivetrain vibration at idle in gear, Difficulty engaging gears smoothly, Visible transmission sag when inspected on lift

Fix: Rubber mounts collapse from age and engine torque. Replace all transmission and engine mounts as a set for best results. 3-4 hours labor. Aftermarket polyurethane mounts available but increase NVH.

Estimated cost: $400-700

Symptoms: Intermittent no-start conditions, Engine dies randomly while driving, Erratic fuel delivery and ignition timing, No communication with diagnostic equipment

Fix: 30-year-old capacitors in ECU leak or fail, causing total loss of engine management. Remove ECU, send to specialist for capacitor replacement and board inspection. 1 hour removal/reinstall labor plus 1-2 week turnaround. Few shops do this work—mostly mail-order rotary specialists.

Estimated cost: $400-800