The 2016 Sequoia is built on Toyota's bulletproof truck platform, but the 5.7L V8 (most common) has a documented air-injection system failure issue that can grenade engines if ignored, plus transmission cooler line corrosion that's common in rust-belt states.
Secondary Air Injection Pump Failure Leading to Catastrophic Engine Damage
Occasional · high severityTypical onset: 80,000-150,000 mi
Symptoms: Check engine light with P0410/P0418 codes (air injection system), Rattling noise from front of engine at cold start, Metal shavings in oil or sudden loss of oil pressure if pump disintegrates, Complete engine failure if pump bearing fragments enter intake manifold
Fix: If caught early, replace air injection pump and check valve assembly (3-4 hours labor). If pump grenades and metal enters cylinders, you're looking at complete engine rebuild or replacement — new pistons, rings, bearings, machine work, 40-60 hours labor. This is the nightmare scenario that shows up in those 'engine rebuild' repair records.
Estimated cost: $800-1,200 for pump replacement; $8,000-15,000 for full engine rebuild/replacement
Transmission Oil Cooler Line Corrosion and Leaks
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Red ATF dripping from radiator area or frame rails, Transmission temp light illuminating under load, Crusty rust buildup on steel cooler lines where they pass through frame, Low transmission fluid discovered during service
Fix: Steel transmission cooler lines rust through where they're exposed to road salt and debris. Replace both lines from radiator to transmission (don't patch), plus flush cooler and check for cross-contamination if leak was at radiator. 3-4 hours labor, more if you need to drop skid plates.
Estimated cost: $600-1,000
Lower Ball Joint Wear and Steering Wander
Common · medium severityTypical onset: 80,000-130,000 mi
Symptoms: Clunking over bumps from front suspension, Steering feels loose or requires constant correction on highway, Uneven inner tire wear on front wheels, Play in wheel when lifted and pushed/pulled at 12-6 o'clock
Fix: Lower control arm ball joints wear out from the sheer weight of this truck. Toyota doesn't sell the joint separately on these — you replace the entire lower control arm assembly. Do both sides, get alignment. 4-5 hours labor for both sides.
Estimated cost: $800-1,200
Rear Differential Pinion Seal Leak
Occasional · low severityTypical onset: 90,000-150,000 mi
Symptoms: Gear oil dripping from front of rear differential, Oil buildup on differential housing and driveshaft, Whining noise from rear end if fluid runs low
Fix: Pinion seal weeps oil over time. Not urgent if caught early, but don't let it run dry. Replace seal, check pinion preload, refill with 75W-85 gear oil. 2-3 hours labor if no other damage.
Estimated cost: $300-500
Exhaust Manifold Stud Breakage (4.6L V8)
Occasional · medium severityTypical onset: 100,000+ mi
Symptoms: Ticking or tapping noise from engine that changes with RPM, Exhaust smell in cabin, Visible soot around manifold-to-head interface, Check engine light with O2 sensor codes if leak is severe
Fix: The 4.6L (less common in 2016, but some fleet units have it) has notorious exhaust manifold stud issues. Studs corrode and snap, requiring manifold removal and drilling/tapping for new studs or Heli-Coil inserts. 6-8 hours per side if you need to extract broken studs. 5.7L is far less prone to this.
Estimated cost: $800-1,500 per side
Power Steering Rack Seal Leaks (Related to NHTSA Recalls)
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Power steering fluid dripping from rack boots, Steering feels heavy or notchy at low speeds, Groaning noise when turning wheel lock-to-lock, Pump whine if fluid level drops
Fix: The hydraulic steering system (Toyota recalled some units for assist motor issues) can develop rack seal leaks. If caught early, replacing rack seals is possible but labor-intensive. Most shops quote a remanufactured rack instead — 4-5 hours labor, requires alignment after.
Estimated cost: $1,000-1,800
A solid long-term truck if you address the air-injection pump proactively and avoid high-mileage examples with deferred maintenance — engine damage from failed pumps is the only real financial landmine here.
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.