The 2021 ES 350 is generally solid, but the 8-speed automatic (8AR-FTS related transmission) can develop oil cooler leaks, and isolated cases of catastrophic engine failure due to bore scoring exist—rare but expensive when they hit.
Transmission Oil Cooler Leak
Occasional · medium severityTypical onset: 40,000-80,000 mi
Symptoms: Pink or red fluid pooling under vehicle near front, Transmission running hotter than normal, Low transmission fluid warning on dash, Burnt transmission fluid smell
Fix: Replace transmission oil cooler assembly and lines. Requires dropping front subframe for access. 4-6 hours labor plus parts. Flush and refill transmission fluid.
Estimated cost: $1,200-2,000
Catastrophic Engine Failure (Bore Scoring/Piston Damage)
Rare · high severityTypical onset: 30,000-70,000 mi
Symptoms: Sudden loss of power and loud knocking noise, Metal shavings in oil during change, White or blue smoke from exhaust, Check engine light with misfire codes, Extremely low oil pressure
Fix: Complete engine rebuild or short block replacement required. Cylinder bore scoring leads to ring failure and catastrophic damage. 25-35 hours labor for short block swap, plus machine work if rebuilding. Some cases covered under extended warranty campaigns.
Estimated cost: $8,000-15,000
Transmission Mount Failure
Occasional · low severityTypical onset: 60,000-100,000 mi
Symptoms: Clunking when shifting from Park to Drive, Excessive vibration at idle, Visible sagging or cracking of rubber mount, Transmission movement felt through shifter
Fix: Replace failed transmission mount(s). Front mount most common. 2-3 hours labor. Straightforward job but requires supporting transmission.
Estimated cost: $400-700
Fuel System Carbon Buildup (Direct Injection)
Common · low severityTypical onset: 50,000-100,000 mi
Symptoms: Rough idle when cold, Hesitation on acceleration, Reduced fuel economy, Check engine light with misfire codes (P0300-P0306)
Fix: Walnut blast intake valves to remove carbon deposits. Direct injection engines lack fuel wash over valves. 4-6 hours labor for thorough cleaning. Some shops use chemical induction cleaning as temporary measure (1 hour).
Estimated cost: $500-900
Head Gasket Failure (Related to Bore Scoring Issue)
Rare · high severityTypical onset: 40,000-80,000 mi
Symptoms: Coolant loss with no visible leaks, White exhaust smoke, Overheating, Milky oil on dipstick, Bubbles in coolant reservoir
Fix: Replace both head gaskets. Often discovered during diagnosis of cooling system issues or as secondary damage from bore scoring problem. 18-22 hours labor. Requires machine shop to check head flatness.
Estimated cost: $3,500-5,500
Buy with confidence if pre-purchase inspection shows normal oil consumption and no transmission leaks—most are bulletproof, but budget for carbon cleaning and verify engine history.
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.