The 2022 4Runner is actually powered by a 4.0L V6 (1GR-FE), a proven engine dating back to 2003, but one with a known Achilles heel: secondary air injection system failures and head gasket issues at higher mileages. The transmission and drivetrain are solid, but the engine's age means you're buying 20-year-old tech with its associated quirks.
Secondary Air Injection System Failure (Check Engine Light P0410/P0441)
Common · low severityTypical onset: 60,000-100,000 mi
Symptoms: Check engine light with P0410, P0411, P0441 codes, Rattling noise on cold starts from stuck air pump, Failed emissions testing in states that monitor secondary air
Fix: Replace secondary air injection pump and/or check valves. Some techs delete the system in non-emissions states, but proper fix is replacement. 2-3 hours labor for pump, 1 hour for valves.
Estimated cost: $800-1,400
Head Gasket Failure (External Coolant Leaks)
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: Coolant weeping from head/block mating surface, visible as white residue, Slow coolant loss without visible leaks elsewhere, Sweet smell from engine bay after driving, In severe cases, coolant in oil (milky dipstick)
Fix: Both head gaskets, head resurfacing, timing components while in there, new water pump. This is a 16-20 hour job due to tight engine bay. Many shops recommend doing both heads even if only one is leaking.
Estimated cost: $3,500-5,500
Transmission Oil Cooler Line Corrosion
Occasional · medium severitySymptoms: Transmission fluid dripping near radiator or under front of vehicle, Pink or red fluid spots on driveway, Low transmission fluid level on dipstick
Fix: Replace corroded transmission cooler lines (common in rust belt). If caught early, it's just lines. If run low, you're looking at transmission damage. 2-3 hours for lines only.
Estimated cost: $400-700
Front Lower Ball Joint Wear
Common · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Clunking over bumps from front suspension, Wandering or loose steering feel, Uneven tire wear on inside edges, Failed safety inspection for ball joint play
Fix: Replace lower ball joints (often both sides). Some techs replace entire lower control arms for easier install. 3-4 hours for both sides with alignment.
Estimated cost: $800-1,200
Exhaust Manifold Crack/Leak (Right Bank)
Occasional · low severityTypical onset: 100,000-150,000 mi
Symptoms: Ticking noise on cold start that fades as engine warms, Exhaust smell in cabin with heat on, Visible soot or black marks on right-side manifold
Fix: Replace cracked exhaust manifold. Right side is more accessible than left. Some aftermarket options available but OEM lasts longer. 4-5 hours labor right side.
Estimated cost: $900-1,500
Rear Differential Pinion Seal Leak
Occasional · low severityTypical onset: 70,000-110,000 mi
Symptoms: Gear oil dripping from front of rear differential, Oil spots on driveway behind vehicle, Low differential fluid level (check fill plug)
Fix: Replace pinion seal, check pinion bearing preload, refill with 75W-85 GL-5. If caught early, just a seal. If run dry, bearings are damaged. 2-3 hours if just seal.
Estimated cost: $400-650
Solid truck with a dated but proven V6—just budget for head gaskets after 120k and stay on top of the secondary air system; otherwise, these run forever.
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.