The 2007 Buick Lucerne is GM's W-body luxury sedan that rides on proven architecture but suffers from significant powertrain issues, particularly catastrophic V8 engine failures and transmission cooler problems that can kill the 4T65-E transaxle if ignored.
4.6L Northstar V8 Catastrophic Engine Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: excessive oil consumption (quart per 500-1000 miles), white smoke from exhaust on startup, coolant loss with no visible leaks, rough idle and misfires, eventually complete loss of compression
Fix: Head gasket failure allows coolant into cylinders, warping heads and scoring cylinder walls. Requires engine rebuild with new pistons, rings, head gaskets, and often crankshaft work. Some owners opt for used engine replacement instead. 25-35 labor hours for proper rebuild.
Estimated cost: $5,500-9,000
Transmission Oil Cooler Line Failure
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: transmission fluid leaking near radiator, pink residue under vehicle, transmission slipping or delayed engagement, coolant in transmission pan (cross-contamination), transmission overheating
Fix: Steel cooler lines rust through where they connect to radiator, or internal cooler fails mixing coolant and ATF. If caught early, replace lines and flush (3 hours). If cross-contaminated, transmission rebuild required (12-16 hours) plus cooler/line replacement.
Estimated cost: $300-500 (lines only) / $2,800-4,200 (with transmission rebuild)
3.8L Series II/III Intake Manifold Gasket Failure
Common · medium severityTypical onset: 90,000-150,000 mi
Symptoms: coolant loss without visible external leaks, white smoke from exhaust, rough idle when cold, DexCool residue around intake plenum, overheating in severe cases
Fix: Plastic intake manifold gaskets deteriorate and allow coolant into crankcase or combustion chambers. Requires upper intake removal, new gaskets, thermostat housing replacement while you're in there. 5-7 labor hours. Often combined with spark plug replacement.
Estimated cost: $800-1,400
Ignition Lock Cylinder Failure
Occasional · high severitySymptoms: key won't turn or gets stuck in ignition, no crank/no start even with good battery, steering wheel locks and won't release, ignition cylinder loose or floppy
Fix: GM ignition lock cylinders wear internally; some units subject to recall for potential stalling while driving. Replacement requires steering column disassembly and programming new cylinder to existing key. 2-3 labor hours. Often covered under extended recall.
Estimated cost: $350-650 (if not recall-covered)
Power Steering Pump and Rack Leaks
Occasional · medium severityTypical onset: 100,000-160,000 mi
Symptoms: power steering fluid puddles under front of car, whining noise when turning, heavy steering effort especially when cold, fluid on inner CV boot area
Fix: Pump seals fail or rack develops leaks at inner tie rod boots. Pump replacement is 2 hours, rack is 4-5 hours. Often see both pump and high-pressure hose need replacement together due to contamination from leaked fluid.
Estimated cost: $400-700 (pump) / $900-1,500 (rack)
4T65-E Transmission Mount Collapse
Common · low severityTypical onset: 80,000-130,000 mi
Symptoms: severe clunk when shifting from park to drive or reverse, excessive engine rocking during acceleration, vibration at idle in gear, visible sagging of powertrain on driver's side
Fix: Hydraulic transmission mount fails allowing excessive powertrain movement. Straightforward replacement but requires supporting engine/trans safely. 1.5-2 hours labor. Use OEM or quality aftermarket; cheap mounts fail within a year.
Estimated cost: $250-400
Blower Motor Resistor Failure
Occasional · low severitySymptoms: HVAC blower only works on high speed, intermittent blower operation, no air flow from vents on lower speeds, burning smell from vents (if motor failing too)
Fix: Resistor module overheats and fails, usually due to aging blower motor drawing excess current. Located behind glove box for easy access. Replace resistor and inspect blower motor condition. 0.5-1 hour labor. Consider replacing blower motor preventively if original.
Estimated cost: $150-300
The V6 models are serviceable used cars if the intake gaskets have been done and the trans cooler lines are solid; avoid the V8 unless you enjoy expensive surprises or can wrench yourself.
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.