The 2009 Highlander is generally solid, but the 3.5L V6 has a serious oil consumption defect that can grenade engines, and all models share transmission cooler line and mount issues that need proactive attention.
3.5L V6 Excessive Oil Consumption / Engine Failure
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Blue smoke from exhaust on cold start or acceleration, Burning 1+ quart of oil every 1,000 miles, Check engine light with misfire codes (P0300-P0306), Knocking or ticking noise from engine if oil starvation occurs, Catastrophic engine failure if oil level not monitored closely
Fix: Root cause is defective piston rings from 2007-2009 production. Toyota had a warranty enhancement (ZE3) but it expired. Proper fix requires engine rebuild with updated pistons/rings (35-45 hours) or short block replacement (30-40 hours). Some owners limp along adding oil constantly until failure.
Estimated cost: $5,500-8,500
Transmission Oil Cooler Line Leak
Common · medium severityTypical onset: 100,000-160,000 mi
Symptoms: Transmission fluid dripping near radiator or under engine, Pink or red fluid puddles on driveway, Transmission slipping or delayed engagement if fluid level drops, Low fluid on dipstick check
Fix: Steel cooler lines rust through where they pass near subframe or connect to radiator. Must replace lines (OEM or aftermarket stainless upgrades available). Labor is 2-3 hours due to access under vehicle and flushing system. Inspect closely during any service — catching early prevents transmission damage.
Estimated cost: $400-700
Rear Transmission Mount Failure
Common · low severityTypical onset: 90,000-140,000 mi
Symptoms: Clunk or thud when shifting from Park to Drive or Reverse, Vibration through floor or steering wheel at idle in Drive, Excessive engine movement visible when revving in Park, Rougher than normal gear changes
Fix: Rubber mount separates or tears, allowing powertrain to shift excessively. Replacement is straightforward — support transmission with jack, remove 4-6 bolts, swap mount (1.5-2 hours). Inspect front mount at same time as it often fails within 20k miles after rear.
Estimated cost: $250-450
Front Strut Mount Bearing Noise
Occasional · low severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking or popping from front end over bumps, Grinding or creaking when turning steering wheel while stopped, Steering wheel doesn't return to center smoothly, Uneven tire wear on inside edges
Fix: Upper strut mount bearings wear out, especially in cold climates or with heavy loads. Replace mounts in pairs during strut replacement or separately if struts still good (2-2.5 hours per side including alignment). Always do alignment after — this affects camber/caster.
Estimated cost: $400-650
VVT-i Cam Gear Oil Line Leak (3.5L V6)
Occasional · medium severityTypical onset: 120,000-180,000 mi
Symptoms: Oil seeping from timing cover area on front of engine, Rough idle or hesitation on cold start, Check engine light with P0010/P0020 (VVT system performance), Oily residue visible on front of engine below valve covers
Fix: O-rings on variable valve timing oil supply lines harden and leak. Requires removing front timing cover to access (8-12 hours). While in there, smart shops replace cam seals, crank seal, and water pump. Not urgent if leak is slow but will worsen and can trigger VVT codes.
Estimated cost: $1,200-2,000
Evaporative Emissions Charcoal Canister Failure
Occasional · low severityTypical onset: 90,000-150,000 mi
Symptoms: Check engine light with P0446 or P0441 (EVAP system codes), Difficulty filling gas tank — pump shuts off repeatedly, Fuel smell near rear of vehicle, Hissing sound when opening fuel cap
Fix: Charcoal canister under vehicle near fuel tank clogs or cracks, often from water intrusion or fuel contamination. Replace canister and inspect all EVAP lines/valves (1.5-2 hours). Not safety-critical but will fail emissions testing. Toyota redesigned part after 2009 — get updated version.
Estimated cost: $350-600
Buy the 2.7L I4 or hybrid without hesitation; avoid the 3.5L V6 unless engine has already been rebuilt with updated parts or you enjoy checking dipsticks obsessively.
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.