1989 BUICK CENTURY

Typical onset: 90,000-140,000 mi

Symptoms: Excessive oil consumption (1 qt per 500-800 miles), Rod knock or main bearing knock at startup, Blue smoke from exhaust on deceleration, Low oil pressure warning at idle when warm

Fix: This engine burns oil from worn rings and can spin bearings prematurely due to marginal oiling design. Full rebuild or replacement required - expect 16-22 labor hours for engine R&R plus rebuild time. Most owners opt for a junkyard replacement over rebuild due to age.

Estimated cost: $1,800-3,200

Typical onset: 70,000-110,000 mi

Symptoms: Coolant loss with no visible external leaks, White smoke from exhaust on cold start, Rough idle and misfires, Milky oil if severe

Fix: The lower intake gasket fails, allowing coolant into the crankcase or cylinders. Intake manifold removal and gasket replacement takes 4-6 hours. Must resurface intake if warped. Often done with thermostat and water pump while you're in there.

Estimated cost: $450-850

Typical onset: 60,000-100,000 mi

Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive engine movement visible from driver's seat, Vibration at idle in gear, Shifter feels notchy or catches

Fix: The front transmission mount (engine side) fails from oil contamination and age. The rubber deteriorates and the trans shifts forward under load. Replacement is 1.5-2.5 hours - straightforward but requires supporting the powertrain. Replace both motor mounts at same time if original.

Estimated cost: $180-350

Typical onset: 100,000-150,000 mi

Symptoms: Slipping between gears, especially 2nd to 3rd, Delayed engagement when cold, No reverse or intermittent reverse, Whining noise in gear

Fix: The TH125C (also called 3T40) has weak 2nd gear components and the torque converter clutch frequently fails. Rebuild runs 12-16 hours, but finding quality parts is difficult. Used replacement often more cost-effective. Fluid changes every 30k miles help but won't prevent eventual failure.

Estimated cost: $1,200-2,200

Typical onset: 80,000-130,000 mi

Symptoms: No-start with crank but no fire, Stalling when fuel tank below 1/4, Whining noise from rear seat area, Intermittent dying at highway speed

Fix: The in-tank electric fuel pump fails from wear and contamination. Must drop fuel tank for access - 2.5-3.5 hours labor. Replace fuel filter and strainer sock at same time. Running tank low frequently accelerates pump death.

Estimated cost: $350-600

Symptoms: Transmission fluid leak at radiator connections, Pink fluid pooling under front of car, Low transmission fluid level, Transmission slipping after fluid loss

Fix: Steel cooler lines rust through at the radiator connections or where they run along the frame. Requires replacement of affected lines - 1.5-2.5 hours depending on which line fails. In rust-belt cars, both lines often need replacement at once. Refill and check for cross-contamination if leak is at radiator.

Estimated cost: $200-450

Typical onset: 60,000-120,000 mi

Symptoms: No-start when engine is hot, starts fine cold, Random stalling in traffic, Intermittent loss of spark to all cylinders, No codes stored, fails intermittently

Fix: The HEI distributor ignition module fails from heat cycling. Classic symptom is no-start when hot, then works after cooling. Module replacement is 0.5-1 hour, but diagnostic time can exceed repair time due to intermittent nature. Replace pickup coil at same time if original.

Estimated cost: $150-300