The 1991 MX-6 shares its platform with the Ford Probe and uses Mazda's F2/F2T engines. Turbos are fun but fragile; naturally-aspirated models are more reliable but both suffer from transmission cooling issues and typical early-90s Mazda rust. Engine rebuild frequency in the data tells you these motors don't always make it past 150k without serious internal work.
Automatic Transmission Overheating and Failure (F4A-EL)
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: Harsh shifting or slipping between 2nd and 3rd gear, Burnt ATF smell, dark or metallic fluid, Complete loss of forward gears after highway driving, Transmission cooler lines leaking at radiator or cooler connections
Fix: The external transmission oil cooler fails or gets blocked, cooking the transmission. If caught early, replace cooler and flush (2-3 hours labor). If internal damage occurred, expect rebuild or replacement (8-12 hours). Many shops won't rebuild these — used units common.
Estimated cost: $400-800 for cooler/flush, $1,800-3,200 for rebuild or used trans swap
Turbo Engine Internal Failure (F2T - Piston Ringland Cracks)
Occasional · high severityTypical onset: 90,000-130,000 mi
Symptoms: Excessive blue smoke on startup and under boost, Loss of compression in one or more cylinders, Oil consumption over 1 quart per 500 miles, Rattling noise from engine under load, pre-detonation knock
Fix: The F2T loves to crack piston ringlands, especially if boost was turned up or maintenance skipped. Requires engine-out rebuild with new pistons, rings, bearings, and often head work. 16-24 hours labor depending on shop speed and parts availability. Many owners swap in used engines instead.
Estimated cost: $2,500-4,500 for rebuild, $1,200-2,000 for used engine swap
Head Gasket Failure (Both Engines)
Common · medium severityTypical onset: 100,000-150,000 mi
Symptoms: White smoke from exhaust, sweet smell, Coolant loss with no visible leaks, Oil milkshake on dipstick or under oil cap, Overheating, especially under load or in traffic
Fix: Both F2 and F2T suffer head gasket leaks, often between cylinders or into coolant passages. Requires head removal, machining check, new gasket set, timing belt while you're in there. 8-12 hours labor. Turbo motors sometimes warp heads if overheated.
Estimated cost: $1,200-2,000 including timing belt and water pump
Rear Trailing Arm Bushings and Strut Tower Rust
Common · medium severitySymptoms: Clunking over bumps from rear suspension, Rear alignment won't hold, tire wear on inside edges, Visible rust perforation around rear strut towers, Rear end feels loose or unstable in corners
Fix: Trailing arm bushings rot out by 80k-100k miles, causing alignment and handling issues. 3-4 hours for bushings. The real killer is rust in rear strut towers and subframe mounts — structural and expensive to fix properly. Inspect before buying.
Estimated cost: $400-700 for bushings, $1,500+ for strut tower rust repair if catch-able
Power Window Regulator Failure
Occasional · low severityTypical onset: 60,000-120,000 mi
Symptoms: Window drops into door, won't raise, Grinding or clicking noise when operating window, Window tilts or binds in track, Motor runs but window doesn't move
Fix: Plastic regulator components and cables fail, especially driver's side. Requires door panel removal and regulator replacement. 1.5-2.5 hours per door. Used parts often in same condition.
Estimated cost: $250-450 per door
Fuel System Issues (Filter, Pump, Injector Seals)
Occasional · medium severityTypical onset: 80,000-140,000 mi
Symptoms: Hard starting when hot, long crank before fire, Stumble or hesitation under acceleration, Fuel smell in cabin or visible leak at rail, Check engine light with lean codes
Fix: In-tank pump weakens with age, filter gets neglected (it's under car, requires lift). Injector o-rings leak. Replace fuel filter every 30k (0.5 hour). Pump replacement 2-3 hours, injector seals 2-3 hours if you catch leaks early.
Estimated cost: $150-250 for pump, $300-500 for injector service
Buy a naturally-aspirated manual if you find a rust-free example under 100k miles; skip high-mileage turbos and any automatic unless you can verify recent cooler and fluid service.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.