2002 TOYOTA 4RUNNER

Symptoms: visible surface rust on frame rails, especially rear crossmember, flaking and scaling near spare tire carrier mounts, perforation holes in C-channel sections, failed state inspection in rust-belt states

Fix: Inspection every oil change is critical. Surface rust can be wire-brushed and coated (2-4 hours DIY). Perforation means frame replacement (30-40 hours) or vehicle retirement. Toyota issued a frame replacement program through 2016 but it's expired.

Estimated cost: $8,000-12,000

Typical onset: 80,000-150,000 mi

Symptoms: clunking over bumps, wandering steering, inner tire edge wear, grease boot torn or missing, catastrophic separation if ignored

Fix: Factory ball joints are pressed into the lower control arm and not serviceable separately. Requires entire lower control arm replacement both sides. 3-4 hours per side, alignment required. This was subject to NHTSA recall but many were never done.

Estimated cost: $800-1,200

Typical onset: 100,000-180,000 mi

Symptoms: gear oil dripping from front of rear diff, oil coating underside of diff housing, low fluid causes whining under acceleration

Fix: Pinion seal replacement requires removing driveshaft, pinion nut, and resetting pinion bearing preload with crush sleeve. Critical to mark pinion position before disassembly. 2-3 hours labor if done correctly first time.

Estimated cost: $400-700

Typical onset: 120,000-200,000 mi

Symptoms: transmission fluid leaking near radiator, pink fluid in coolant overflow, transmission overheating and slipping, milkshake-colored fluid on dipstick if cooler ruptured internally

Fix: External line failure requires replacing steel lines (1.5 hours). Internal rupture into radiator is catastrophic—contaminates both systems and requires radiator, transmission flush, and often transmission rebuild. Catch it early with regular coolant inspection.

Estimated cost: $300-500

Typical onset: 150,000-250,000 mi

Symptoms: external coolant weeping between head and block, white smoke on cold start, bubbles in coolant overflow when running, rough idle when warmed up

Fix: External leaks are more common than internal. Both heads require removal, resurfacing, new gaskets, timing belt replacement while apart. 18-22 hours labor. Engine must come out or be lifted significantly on 4WD models for rear head access.

Estimated cost: $2,500-3,800

Typical onset: 100,000-180,000 mi

Symptoms: ticking noise on cold start that diminishes when warm, exhaust smell in cabin, visible soot streaks on manifold, broken or stripped manifold studs

Fix: Manifolds crack between ports or at EGR tube boss. Studs corrode and break in head. Requires manifold removal (4-6 hours per side), stud extraction, head thread repair or helicoil, new manifolds or quality aftermarket headers. Rear bank is cramped.

Estimated cost: $800-1,400

Typical onset: 120,000-200,000 mi

Symptoms: no-start when engine is hot, single click with no crank, starts fine when cold or after sitting 30+ minutes, voltage drop test shows starter drawing excessive current when hot

Fix: Starter sits against exhaust manifold and solenoid contacts wear from heat cycling. Replacement requires removing skid plate and starter heat shield. 1.5-2 hours. OEM Toyota starters last twice as long as most aftermarket rebuilds in this application.

Estimated cost: $400-650