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2021 TOYOTA 4RUNNER

4.0L V6•4WD•AUTOMATIC•gas•1GR-FE
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5-Year Cost of Ownership
$11,802 maintenance + known platform issues
~$2,360/yr · 200¢/mile equivalent · $6,371 maintenance + $4,731 expected platform issues
Compare this engine
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2.4L Turbo I4 i-FORCE (T24A-FTS)
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4.7L V8

Common Problems & Known Issues

The 2021 4Runner with the 4.0L V6 (1GR-FE) is a generally solid truck, but the frequent transmission oil cooler failures and well-documented secondary air injection issues can bite owners hard. Engine rebuild frequency in the data suggests either premature wear from deferred maintenance or aftermarket abuse.

Transmission Oil Cooler Failure / Transmission Contamination

Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Milky or pink transmission fluid (coolant mixing), Transmission slipping, delayed shifts, or limp mode, Overheating transmission temp gauge reading
Fix: Replace external cooler and flush system if caught early (2-3 hrs). If coolant entered transmission, full rebuild or replacement required (12-18 hrs labor). This is a known Toyota weak point across multiple platforms.
Estimated cost: $800-6,500

Secondary Air Injection System Failure (P0410, P0418, P0419)

Common · low severity
Typical onset: 70,000-110,000 mi
Symptoms: Check engine light with P0410/P0418/P0419 codes, Rattling or buzzing noise on cold start for 60-90 seconds, No drivability issues, emissions test failure in strict states
Fix: Air pump or one-way valves fail. Pump replacement 2 hrs, valve replacement 1.5 hrs. Many owners delete the system entirely if emissions testing allows (1 hr plus tune).
Estimated cost: $600-1,400

Front Lower Ball Joint Wear

Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Clunking over bumps at low speed, Wandering steering or loose feel, Uneven tire wear on inside edge
Fix: Ball joints are pressed into lower control arms. Replace both sides (alignment required). 3-4 hrs labor. Aftermarket heavy-duty options available for off-road use.
Estimated cost: $700-1,200

Exhaust Manifold Leak / Cracking (Driver Side)

Occasional · low severity
Typical onset: 90,000-150,000 mi
Symptoms: Ticking or tapping noise from engine bay on cold start, Smell of exhaust in cabin with heat on, Visible soot around manifold gasket area
Fix: Driver-side manifold cracks or gasket fails. Manifold replacement is 5-6 hrs due to tight clearances. Gasket-only job if caught early is 3 hrs.
Estimated cost: $800-1,800

Premature Piston Ring Wear / Oil Consumption (Abused or Neglected Units)

Rare · high severity
Typical onset: 100,000-180,000 mi
Symptoms: Burning more than 1 quart per 1,000 miles, Blue smoke on deceleration or startup, Low compression on cylinder leak-down test
Fix: The 1GR-FE is typically bulletproof, but extended oil changes or aggressive off-road use without proper cooling can cause premature ring wear. Engine rebuild or short-block replacement: 18-24 hrs labor.
Estimated cost: $4,500-8,000

Radiator Plastic Tank Cracking

Occasional · medium severity
Typical onset: 100,000-140,000 mi
Symptoms: Coolant leak from radiator end tank, Overheating under load or in traffic, Visible coolant pooling under vehicle
Fix: Plastic end tanks crack with age and heat cycles. Radiator replacement is straightforward: 2 hrs labor. Use OEM or quality all-aluminum aftermarket.
Estimated cost: $400-800

Fuel Pump / Fuel Filter Issues (Post-Contaminated Fuel)

Rare · medium severity
Symptoms: Hard starting after sitting, Sputtering or stumbling under acceleration, Check engine light with fuel trim codes
Fix: In-tank pump and filter are combined. Failure is rare unless bad fuel introduced. Drop tank, replace pump assembly: 3 hrs labor.
Estimated cost: $600-1,100
Owner tips
  • Change transmission fluid every 50k-60k miles even though Toyota says 'lifetime'—cooler failures contaminate fluid and kill transmissions.
  • Inspect front lower ball joints at every alignment; replace before they fail to avoid control arm damage.
  • If secondary air codes appear, verify pump operation before replacing valves—both fail independently.
  • Use 0W-20 synthetic and stick to 5k-7k oil changes if you off-road or tow; the 1GR-FE hates extended intervals under load.
  • Check radiator end tanks for hairline cracks during coolant service at 100k—catch it before it strands you.
Buy it used—the 4Runner is dead-reliable if maintained, just budget $1,500 for the inevitable trans cooler and secondary air repairs around 80k miles.
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.

Labor Times — 2021 Toyota 4Runner

500 jobs across 17 categories

body (31)

brakes (44)

cooling (21)

drivetrain (36)

electrical (75)

engine (67)

exhaust (23)

hvac (23)

interior (24)

maintenance (32)

steering (23)

suspension (40)

transmission (30)

🔧 Built by master technician Chris Hackleman · Master Technician · 20+ years.
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