2004 LEXUS ES 300

Typical onset: 100,000-150,000 mi

Symptoms: Harsh shifts or flaring between 2nd and 3rd gear, Slipping under acceleration, especially when warm, Delayed engagement when shifting from Park to Drive, Transmission fluid burnt smell or dark brown color, Check engine light with P0700, P0770, or P0773 codes

Fix: The U140/U151 trans in these cars has weak direct clutch packs that fail prematurely. Full rebuild requires 12-16 hours, including torque converter replacement and updated friction materials. External oil cooler lines also leak at crimped fittings around this mileage and contaminate fluid, accelerating wear. Some shops only replace the cooler and flush, buying time, but most need full rebuilds.

Estimated cost: $2,800-4,200

Typical onset: 120,000-180,000 mi

Symptoms: Burning a quart of oil every 800-1,200 miles, Blue smoke from exhaust on cold start or acceleration, Oil pressure warning light flickers at idle when hot, Rattling noise from valvetrain on cold starts, Visible sludge on oil cap or valve covers when opened

Fix: The 1MZ-FE is prone to piston ring wear and oil control ring clogging, especially if oil changes were stretched. Owners who didn't do 5,000-mile synthetic changes often see severe sludge. Minor cases can limp along with frequent top-offs, but advanced consumption requires engine teardown: new rings, honing, valve seals, and full desludge. That's 18-24 hours. Complete engine swaps from low-mileage JDM units run 14-18 hours and are sometimes more cost-effective than rebuilds.

Estimated cost: $3,500-6,000

Typical onset: 80,000-120,000 mi

Symptoms: Clunk or thud when shifting from Park to Reverse or Drive, Vibration through steering wheel or floorboard at idle, Excessive engine movement visible when revving in Park, Rattling over bumps that sounds like loose exhaust

Fix: The hydraulic front mount and the rear mount both fail from age and fluid leaks. Front mount replacement is 2-3 hours due to tight access; rear mount is about 1.5 hours. Most shops do both at once since labor overlaps and one failed mount overloads the other. OEM mounts last longer than aftermarket.

Estimated cost: $600-900

Typical onset: 100,000-140,000 mi

Symptoms: Fluid drips or puddles under front center of car, Whining or groaning noise when turning at low speed, Steering feels notchy or sticky in cold weather, Low power steering fluid warnings or repeated top-offs

Fix: The rack develops leaks at the inner tie rod boots and at the input shaft seal. Some techs try stop-leak additives or just keep topping off, but once it's dripping steadily you're looking at rack replacement: 4-5 hours including alignment. Pumps can also fail but the rack is more common on this chassis.

Estimated cost: $1,200-1,800

Typical onset: 120,000-160,000 mi

Symptoms: Check engine light with P0420 or P0430 codes, Slightly reduced fuel economy (1-2 mpg drop), Hesitation or stumble on light throttle, Failed emissions test in states with inspection programs

Fix: Bank 1 and Bank 2 downstream O2 sensors fail first, throwing cat efficiency codes even when cats are fine. Replacing sensors is 0.5-1 hour each and often solves it. If cats are truly dead (rare unless severely overheated from misfires), you're at 3-4 hours labor for both and expensive OEM converters due to California emissions design. Most cases are just sensors.

Estimated cost: $250-500 for sensors; $1,800-2,500 if cats needed

Typical onset: 90,000-105,000 mi

Symptoms: No symptoms until catastrophic failure, Engine suddenly dies and won't crank if belt snaps, Coolant leaks from water pump weep hole, Squealing or chirping from timing belt area when cold

Fix: The 1MZ-FE is an interference engine: if the belt breaks, valves meet pistons and you're rebuilding heads or the whole engine. Toyota interval is 90k; many owners skip it because the car runs fine. The job is 4-6 hours and includes belt, tensioner, idler pulleys, and water pump. Skipping this is the single worst financial mistake on this car—belt failure can total the engine.

Estimated cost: $800-1,200 for preventive service; $3,000-5,000+ if belt breaks