The 2002 Buick Century with the 3.1L V6 is a competent FWD sedan undermined by a few catastrophic engine weaknesses and transmission cooler failures. When maintained meticulously it can reach 150k+, but many examples die prematurely from intake gasket or head gasket failures that cascade into complete engine loss.
Symptoms: External coolant leaks at front of engine, often driver side, White smoke from exhaust on cold start, Milky oil on dipstick or cap, Overheating with no obvious leak, Rough idle or misfire from coolant in cylinders
Fix: Replace plastic lower intake gasket set with updated aluminum-backed design; flush contaminated oil; pressure-test cooling system. Job requires upper plenum removal, fuel rail out, throttle body off. 4-6 hours labor for experienced tech, longer if coolant contaminated bearings. If caught late, coolant in oil destroys bearings and requires complete engine rebuild or replacement.
Estimated cost: $600-1,200 if caught early; $2,500-4,500 for short block if bearings damaged
Head Gasket Failure
Occasional · high severity
Typical onset: 80,000-140,000 mi
Symptoms: External coolant seepage from head/block mating surface, Persistent overheating, Coolant loss with no visible leak, White exhaust smoke, Combustion gases in coolant (bubbling reservoir)
Fix: Both heads off, resurface if warped (common), new gaskets, new head bolts, coolant flush. Intake gaskets also done at same time since engine is apart. 8-12 hours labor. Often discovered after intake gaskets were ignored too long.
Estimated cost: $1,800-3,200
Transmission Oil Cooler Line Corrosion / Leaks
Common · medium severity
Typical onset: 90,000-150,000 mi
Symptoms: ATF puddle under engine bay, passenger side front, Burnt smell or low ATF level, Harsh shifting or slipping if level drops significantly
Fix: Steel cooler lines rust through where they pass near subframe or at radiator connections. Replace both lines as a pair with pre-bent OEM or aftermarket set. 2-3 hours labor, requires lifting vehicle and wrestling lines through tight spaces. Flush cooler in radiator if debris suspected.
Estimated cost: $350-650
Transmission Mount Collapse
Common · low severity
Typical onset: 70,000-120,000 mi
Symptoms: Clunk or thud on hard acceleration or when shifting into reverse, Excessive engine movement visible from driver seat, Vibration at idle in Drive
Fix: Hydraulic front transmission mount fails internally. Jack engine slightly, unbolt mount, replace. 1 hour labor, straightforward.
Estimated cost: $150-280
Alternator Bearing Failure
Occasional · medium severity
Typical onset: 100,000-150,000 mi
Symptoms: Grinding or squealing from serpentine belt area, Battery light intermittent or steady, Electrical accessories dimming, Dead battery after short drives
Fix: Valeo alternators common on these; bearings seize or rotor rubs stator. Replace alternator, inspect belt and tensioner. 1.5 hours labor, straightforward top-side access.
Estimated cost: $300-550
Power Steering Pressure Hose Failure
Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Power steering fluid spray under hood, Whining or groaning on turns, Heavy steering effort, Burning smell from fluid on exhaust
Fix: High-pressure hose from pump to rack develops pinhole leaks or splits at crimps. Replace hose, flush system, bleed air. 1.5 hours labor.
Estimated cost: $200-400
Fuel Tank Pressure Relief / Evap Vent Issues
Occasional · low severity
Symptoms: Check Engine light with P0440-range EVAP codes, Fuel tank hissing when cap removed, Difficulty fueling (pump clicks off repeatedly), Fuel smell near tank
Fix: Vent valve on top of tank or rollover valve fails; sometimes tank itself cracks near filler neck. NHTSA recall addressed some tanks but not all failures. Tank drop required for inspection/replacement. 2-3 hours labor for vent valve; 4-5 hours if tank replacement needed.
Estimated cost: $250-450 for vent valve; $600-1,000 for tank
Owner tips
Flush and replace Dexcool coolant with conventional green coolant every 30k miles to slow intake gasket degradation—this is the single most important maintenance item.
Inspect lower intake manifold gaskets at every oil change for seepage; catch it early before coolant mixes with oil.
Change ATF every 50k miles and inspect cooler lines for surface rust annually if you live in salt states.
Keep an eye on coolant level weekly; these engines give little warning before catastrophic overheating.
Only buy if you can verify intake gaskets were already done with updated parts and coolant system is pristine—otherwise you're buying someone else's deferred $3,000 repair bill.
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.
Fitment notes: Side post terminals standard on GM vehicles of this era
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Every control module on the 1997-2005 Buick Century — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
⚠️ Optional on higher trim levels; requires memory position reprogramming by user
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
DORMAN IS RECALLING 979 STEERING KNUCKLES, DORMAN P/NOS. 697-902 AND 697-903, SOLD UNDER DORMAN'S "OE SOLUTIONS<SUP>TM</SUP>" BRAND NAME, AND NAPA P/NOS. 7-8502 AND 7-8503 WHICH WERE SOLD FOR REPLACEMENT USE ON THE VARIOUS VEHICLES LISTED ABOVE. A POTENTIAL MATERIAL OR DESIGN DEFECT COULD RESULT IN THE STEERING KNUCKLE BREAKING IN THE HUB AREA.
Consequence: A BROKEN STEERING KNUCKLE COULD RESULT IN LOSS OF STEERING CONTROL AND A POSSIBLE CRASH WITHOUT WARNING.
Remedy: DORMAN WILL NOTIFY OWNERS AND REPLACE THE DEFECTIVE STEERING KNUCKLES FREE OF CHARGE AND REIMBURSE THE REPAIR FACILITY OR OWNER FOR LABOR. THE RECALL BEGAN ON FEBRUARY 23, 2009. OWNERS MAY CONTACT DORMAN'S TOLL-FREE HOTLINE AT 1-800-523-2492 AND PRESS 5.
CERTAIN DELPHI FUEL PRESSURE REGULATORS, P/NOS. FP10020-11B1, FP10026-11B1, AND FP10027-11B1, SOLD AFTER JANUARY 9, 2007, AS AFTERMARKET EQUIPMENT FOR VARIOUS PASSENGER VEHICLES LISTED ABOVE. THE UNIVERSAL PRESSURE REGULATORS (UPR) WERE PRODUCED WITHOUT AN O'RING AND RETAINER.
Consequence: FUEL MAY LEAK, POSSIBLY RESULTING IN A FIRE.
Remedy: DELPHI WILL NOTIFY OWNERS AND REPLACE THE UPR FREE OF CHARGE. THE RECALL BEGAN ON APRIL 23, 2007. OWNERS CAN CONTACT DELPHI AT 877-411-8770.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2002 Buick Century 3.1L V6 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.