The 2000 SC 300 with the 2JZ-GE inline-six is mechanically solid, but the A340E transmission and cooling system are the Achilles' heels. Engine internals rarely fail unless severely neglected or overheated.
Transmission Oil Cooler Line Failure / Cooler Leaks
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Trans fluid puddling under engine bay, often passenger side, Transmission slipping or delayed engagement when hot, Pink/red fluid mixing with coolant in overflow tank (internal cooler failure)
Fix: Replace external oil cooler lines (prone to rust-through on steel sections) or entire transmission cooler if internal leak contaminates coolant. Flush both systems. 3-5 labor hours depending on cooler location and line routing.
Estimated cost: $600-1,200
Transmission Mount Collapse
Common · medium severityTypical onset: 100,000-160,000 mi
Symptoms: Clunk on 1-2 or 2-3 upshift under moderate throttle, Excessive driveline vibration at idle in gear, Visible sagging or fluid seepage from rubber mount
Fix: Replace rear transmission mount (large hydraulic mount). Requires supporting trans from below, unbolting crossmember. 1.5-2 hours labor.
Estimated cost: $250-450
2JZ-GE Head Gasket Failure (Both Heads)
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: External coolant seepage at head/block joint, usually rear bank, White smoke on cold start that clears quickly, Coolant loss with no visible external leak, Overheating or bubbling in overflow tank
Fix: Pull both heads, resurface, install OEM Toyota MLS gaskets and ARP studs (highly recommended). Replace timing belt, water pump, cam/crank seals while in there. 16-20 hours labor for proper job.
Estimated cost: $2,500-4,000
Radiator and Cooling System Component Aging
Common · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Coolant seepage from radiator end tanks (plastic), Heater core slow leak (sweet smell, passenger floor dampness), Thermostat housing o-ring weep
Fix: Radiator replacement is straightforward (2-3 hours), heater core requires full dash removal (8-10 hours). Thermostat housing resealed in 1 hour. Budget varies wildly by component.
Estimated cost: $400-2,200
Fuel Filter Clogging (In-Tank Sock and Inline)
Occasional · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Hesitation or stumble under hard acceleration, Intermittent lean codes (P0171/P0174), Fuel pump whine gets louder over time
Fix: Inline filter behind driver rear wheel well (1 hour), in-tank sock requires dropping fuel tank and pump assembly (3-4 hours). Both often done together if symptoms are severe.
Estimated cost: $300-700
Lower Control Arm Bushings (Front)
Common · low severityTypical onset: 100,000-150,000 mi
Symptoms: Clunking over bumps at low speed, Steering wander or vague on-center feel, Inside edge tire wear despite alignment
Fix: Replace both lower control arms with bushings installed (easier than pressing). Alignment required after. 2-3 hours per side.
Estimated cost: $600-1,000
Starter Motor Heat Soak Failure
Occasional · medium severityTypical onset: 120,000+ mi
Symptoms: No-crank condition when engine is hot (starts fine cold), Single click from starter solenoid, Problem clears after cooling 20-30 minutes
Fix: Replace starter motor. Accessible from below, but tight quarters near exhaust manifold. 1.5-2 hours labor.
Estimated cost: $350-600
Buy it if maintenance records show trans services and no overheating history; budget $1,500-2,000 for deferred cooling and trans work on higher-mileage examples.
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.