2010 TOYOTA 4RUNNER

Typical onset: 80,000-150,000 mi

Symptoms: Check engine light P0418/P0419 codes for secondary air injection, Ticking/knocking noise on cold start that persists, Metallic rattling from engine bay, Excessive oil consumption (1 qt per 1,000 mi or worse), White/blue smoke on startup

Fix: Failed SAI check valves allow exhaust gas reversal into intake ports, washing oil off cylinder walls and scoring pistons/rings. Once oil consumption starts, it's progressive. Temporary fix is valve replacement (4-6 hrs), but many engines already have damaged rings. Full engine rebuild or replacement required once consumption is severe: 25-35 hrs labor for rebuild, 18-22 hrs for used/reman swap.

Estimated cost: $4,500-8,500

Typical onset: 90,000-140,000 mi

Symptoms: Loud ticking noise from engine bay, worse when cold, Exhaust smell in cabin or under hood, Visible soot/black streaks on manifold, Check engine light P0420 (catalyst efficiency)

Fix: Cast manifolds crack between runners, typically bank 2 (passenger side) first. Must replace with updated Toyota manifolds or aftermarket headers. Both manifolds recommended as preventive measure. 6-8 hrs labor, parts are $800-1,200 OEM per side.

Estimated cost: $1,800-3,200

Typical onset: 100,000-180,000 mi

Symptoms: Transmission fluid leak at radiator connection, Pink fluid pooling under front of vehicle, Low transmission fluid level, Harsh shifting or slipping if leak is severe

Fix: Steel cooler lines corrode where they connect to radiator, especially in salt states. Lines are not sold separately from radiator assembly by Toyota. Aftermarket lines available but require flaring tools. Replace radiator assembly with lines: 4-5 hrs labor. Flush transmission after repair.

Estimated cost: $800-1,400

Typical onset: 80,000-150,000 mi

Symptoms: Gear oil dripping from front of rear diff, Whining noise from rear axle under load, Low differential fluid level, Oil coating on rear driveshaft

Fix: Pinion seal wears from yoke runout or age. Requires driveshaft removal, seal replacement, and pinion preload verification. If caught early, seal-only fix: 2-3 hrs labor. If bearings are damaged from running low on oil, full pinion bearing service adds 4-5 hrs.

Estimated cost: $400-900

Typical onset: 100,000-160,000 mi

Symptoms: Clunking over bumps from front suspension, Wandering or loose steering feel, Uneven tire wear on inside edge, Visible play when prying on control arm

Fix: Lower ball joints are pressed into control arms. Most shops replace entire lower control arm assemblies for warranty/liability. Both sides recommended even if one is marginal. Alignment required after. 3-4 hrs labor for both sides plus alignment.

Estimated cost: $800-1,200

Symptoms: Rear window won't retract or retracts slowly, Grinding noise from tailgate when operating window, Window drops into door or becomes misaligned, Intermittent operation or complete failure

Fix: Plastic regulator gears strip or motor fails. Requires tailgate trim removal and regulator replacement. Window must be secured during repair. 2-3 hrs labor. OEM regulator assembly is $300-450, aftermarket $150-250.

Estimated cost: $450-850