2018 LEXUS ES 300H

Typical onset: 30,000-80,000 mi

Symptoms: Sudden loss of power, metallic knocking from engine bay, Check engine light with misfire codes (P0300-P0304), Metal shavings in oil, low oil pressure warning, Complete engine seizure in worst cases

Fix: Full short-block replacement or complete engine swap. Toyota issued TSB (TSB-0094-18) acknowledging piston/bearing defects from low-speed pre-ignition in 2018-2019 A25A engines. Warranty extensions covered many, but out-of-warranty cases face 18-24 labor hours for short-block or 22-28 hours for long-block. Dealer-only repair due to hybrid system integration.

Estimated cost: $8,000-14,000

Typical onset: 120,000-180,000 mi

Symptoms: Reduced fuel economy (MPG drops from 44 to 35-38 combined), Hybrid system warning light, reduced EV range, Battery cooling fan runs constantly, Rough transitions between gas and electric modes

Fix: Hybrid battery pack replacement is 4-6 hours labor. Many owners opt for remanufactured packs or third-party cell replacement ($1,500-2,500) instead of dealer OEM ($3,800 parts alone). Diagnosis requires HV battery scanner, not DIY-friendly.

Estimated cost: $2,000-5,500

Typical onset: 70,000-110,000 mi

Symptoms: Red ATF drips under front of vehicle near radiator, Transmission temperature warning on dash, Burnt transmission fluid smell, Slipping or harsh engagement in Drive

Fix: E-CVT cooler lines corrode at crimped fittings where they pass through subframe. Requires transmission cooler line assembly replacement, not just re-sealing. 2.5-3.5 labor hours. Must refill and bleed CVT fluid (WS fluid, dealer-specific in many cases).

Estimated cost: $450-850

Typical onset: 80,000-130,000 mi

Symptoms: Clunking when shifting from Park to Drive/Reverse, Vibration at idle that increases with AC compressor on, Engine rocks excessively when accelerating from stop, Visible torn rubber or fluid leaking from mount

Fix: Hydraulic engine mounts fail frequently on hybrids due to constant start/stop cycling. Front mount is 1.5-2 hours, side transmission mount is 2-3 hours (requires supporting powertrain). OEM Toyota mounts strongly recommended over aftermarket for vibration control.

Estimated cost: $350-700

Symptoms: Hybrid system will not start (READY light won't illuminate), Multiple electrical warnings on dash (ABS, VSC, parking brake), Weak crank or clicking when pressing Power button, Dead battery after sitting 3-5 days

Fix: Hybrids are brutal on 12V batteries due to constant computer drain. OEM batteries last 3-5 years max. Replacement is simple (trunk-mounted, 0.3 hours) but MUST register new battery with ECU using Techstream scanner or equivalent, otherwise charging system won't adapt. DIY-friendly if you have the scanner.

Estimated cost: $250-450

Typical onset: 60,000-100,000 mi

Symptoms: Rough idle, especially when engine is cold, Hesitation or stumble during light acceleration, Misfires on one or more cylinders (P0300-P0304), Increased fuel consumption

Fix: D-4S direct injection system prone to intake valve carbon buildup despite dual-injection design. Walnut blasting intake valves is 3-4 hours labor. Fuel injector replacement (if clogged) is 2-3 hours for all four. Some owners use Top Tier fuel + intake cleaner sprays for prevention.

Estimated cost: $450-900