2006 CHEVROLET CHEVY

Typical onset: 80,000-130,000 mi

Symptoms: White smoke from exhaust, especially on cold starts, Coolant loss with no visible leaks, Overheating or fluctuating temperature gauge, Milky oil on dipstick or oil cap

Fix: Head gasket replacement requires cylinder head removal, resurfacing (often warped), and new timing belt/water pump while in there. 8-12 labor hours depending on whether head needs machine work. Many shops recommend doing both gaskets if one fails.

Estimated cost: $1,200-2,200

Typical onset: 90,000-150,000 mi

Symptoms: Loud ticking or tapping noise from top of engine, worse when cold, Check engine light with misfire codes, Loss of power and rough idle, Metallic rattling that doesn't go away after warmup

Fix: The L91 is extremely sensitive to oil change intervals. Sludge buildup starves lifters and cam lobes. Requires cylinder head removal, camshaft replacement, all lifters, and often valve work. 10-14 labor hours. Prevention is critical—5,000 mi oil changes maximum.

Estimated cost: $2,000-3,500

Typical onset: 60,000-100,000 mi

Symptoms: Excessive vibration at idle, especially in Drive, Clunking when shifting from Park to Drive or Reverse, Visible engine movement when revving in Park, Transmission shifting harshly

Fix: The upper transmission mount (torque mount) is undersized for this engine's vibration. Failure is nearly universal. Replacement is straightforward—1.5-2.5 hours. Often both engine and trans mounts are done together as preventive maintenance.

Estimated cost: $200-400

Typical onset: 60,000-80,000 mi (service interval)

Symptoms: Engine suddenly shuts off while driving, Engine cranks but won't start after belt failure, Catastrophic valve and piston damage if belt snaps

Fix: This is an interference engine—belt failure destroys valves and often pistons. Belt replacement is 3-4 hours and should include water pump, tensioner, and idler pulley. If belt snaps, you're looking at head removal, valve job, possible piston replacement: 12-18 hours total.

Estimated cost: $400-700 (preventive) / $2,500-4,500 (after failure)

Typical onset: 100,000-140,000 mi

Symptoms: Severe vibration at all engine speeds, Squealing or grinding from front of engine, Visible wobble of crankshaft pulley, Serpentine belt throwing off or shredding

Fix: The outer ring separates from the hub due to rubber deterioration. Can damage crankshaft sensor, timing belt, or front main seal if it fails catastrophically. Replacement is 2-3 hours but requires special holding tools for the crankshaft bolt (often seized).

Estimated cost: $300-550

Typical onset: 50,000-90,000 mi

Symptoms: Hard starting, especially when hot, Loss of power under acceleration or uphill, Engine stumbling or hesitation, Stalling at idle after driving

Fix: Inline fuel filter is often neglected—should be changed every 30,000 miles but rarely is. Located under vehicle near tank, 0.5-1 hour labor. Cheap insurance against fuel pump failure (pump works harder with restricted filter).

Estimated cost: $80-150

Symptoms: Transmission fluid leaking near radiator, Pink or red fluid puddles under front of car, Low transmission fluid warning or slipping, Transmission overheating

Fix: Steel cooler lines rust through where they route near the subframe, especially in salt-belt states. Lines need replacement—2-3 hours including fluid refill and system flush. Aftermarket lines are often better quality than OE.

Estimated cost: $250-450