2004 LEXUS GS 300

Typical onset: 80,000-150,000 mi

Symptoms: Check engine light with variable valve timing codes (P1349, P1346), Rough idle, poor acceleration, loss of power, Knocking or ticking from engine, especially cold starts, Catastrophic bearing failure, seized engine in severe cases

Fix: If caught early with VVT-i codes, cam gears and oil control valves can be cleaned/replaced (4-6 hours). Once bearings are damaged, you're looking at either complete engine rebuild (25-35 hours) or used engine swap (12-16 hours). Root cause is oil change neglect—Toyota/Lexus had a TSB but no official recall. Always pull valve covers on pre-purchase inspection.

Estimated cost: $800-1,500 for VVT repair, $6,000-9,000 for rebuild, $3,500-5,500 for used engine installed

Typical onset: 100,000-180,000 mi

Symptoms: Pink milkshake in coolant overflow or radiator, Transmission fluid looks foamy or strawberry-colored, Harsh shifting, slipping, or complete transmission failure, Overheating transmission, burnt ATF smell

Fix: The internal transmission cooler in the radiator fails, mixing coolant and ATF—this kills the A650E transmission fast. Requires radiator replacement, complete ATF flush (often multiple times), and external transmission cooler install (3-5 hours total). If coolant contaminated the trans for more than a few drives, you're replacing or rebuilding the transmission (12-18 hours).

Estimated cost: $800-1,200 for radiator/flush/cooler if caught immediately, $3,500-5,000 for used transmission, $4,500-6,500 for rebuild

Typical onset: 90,000-140,000 mi

Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration at idle in gear, smooths out in Park/Neutral, Excessive drivetrain movement visible under throttle, Pronounced shudder during acceleration

Fix: The rear transmission mount (also called crossmember mount) deteriorates from heat and age. Replacement is straightforward—support transmission, unbolt old mount, bolt in new (1.5-2.5 hours). OEM Lexus part recommended; aftermarket can be softer.

Estimated cost: $300-550

Typical onset: 80,000-130,000 mi

Symptoms: Clunking over bumps from front suspension, Steering wander, vague on-center feel, Uneven inner tire wear, Audible creaking when turning at low speed

Fix: Front lower ball joints wear out and cannot be replaced separately—requires entire lower control arm assemblies. Bushings in upper arms also crack. Expect to do both lower arms plus alignment (3-4 hours). Uppers add another 2 hours if needed.

Estimated cost: $800-1,200 for both lower control arms, $1,200-1,600 if uppers also needed

Typical onset: 120,000-180,000 mi

Symptoms: Battery warning light illuminated, Dimming headlights, flickering dash lights, Whining or grinding noise from alternator, No-start after short drives, dead battery repeatedly

Fix: The Denso alternators are reliable but eventually fail from brush wear. Replacement requires serpentine belt removal and is straightforward (1.5-2 hours). Remanufactured units are fine; verify voltage regulator is included.

Estimated cost: $450-700

Typical onset: 100,000-160,000 mi

Symptoms: Whining or groaning when turning, especially cold, Fluid leak from pump or high-pressure line, Heavy steering effort intermittently, Low fluid level repeatedly

Fix: Pump seals leak or internal vanes wear. Pump replacement is accessible (2-3 hours), includes new pressure hose if leaking at crimp. Flush system with fresh fluid to prevent repeat failure. Aftermarket pumps can be noisy—OEM or Aisin preferred.

Estimated cost: $500-800

Typical onset: 150,000+ mi

Symptoms: No-start, cranks but won't fire, Intermittent stalling, especially hot weather, Hesitation under acceleration, loss of power uphill, Whining from rear seat area (tank)

Fix: In-tank pump assembly wears out. Access through rear seat cushion removal, not a drop-tank job on this chassis (1.5-2.5 hours). OEM Denso strongly recommended—cheap pumps fail early.

Estimated cost: $600-900