1987 BUICK CENTURY

Typical onset: 80,000-130,000 mi

Symptoms: slipping between gears, especially 2nd to 3rd, delayed engagement when shifting to Drive, whining or grinding noise during acceleration, transmission fluid dark or burnt smelling

Fix: The 3-speed automatic is the Achilles heel of these cars. Internal clutch packs and governor wear lead to slippage. Rebuild runs 12-16 hours labor, or 8-10 hours for a used/reman swap. Filter and fluid service every 30k can延 life but won't prevent eventual failure.

Estimated cost: $1,400-2,200

Typical onset: 110,000-160,000 mi

Symptoms: blue smoke on startup and acceleration, excessive oil consumption (1 qt per 500-800 miles), loss of power and rough idle, poor compression test results

Fix: The Iron Duke burns oil as rings wear and cylinder walls glaze over. A proper fix requires boring cylinders 0.020-0.030 over, new pistons, rings, and typically rod and main bearings while it's apart. Engine-out rebuild is 18-24 hours; some opt for a junkyard 2.8L V6 swap instead.

Estimated cost: $2,200-3,500

Typical onset: 70,000-110,000 mi

Symptoms: coolant leaking externally at intake edges, white exhaust smoke after cold starts, coolant loss with no visible external puddles, rough idle and misfires from coolant entering cylinders

Fix: The lower intake gasket deteriorates and allows coolant into the crankcase or cylinders. Repair requires upper and lower intake removal, new gaskets, and often new coolant elbows. Book time is 4-6 hours. Check oil for milky appearance before buying.

Estimated cost: $450-750

Typical onset: 130,000-180,000 mi

Symptoms: deep knocking sound from lower engine at idle, oil pressure dropping below 10 psi at hot idle, metallic rattling that increases with RPM, metal shavings visible in oil filter or pan

Fix: The Iron Duke's main bearings wear from inadequate oiling or extended oil change intervals. Once knocking starts, it's a full teardown: crank polishing or replacement, line boring if needed, all bearings. 20-26 hours labor. Most opt for a used engine swap at this point.

Estimated cost: $2,800-4,200

Typical onset: 60,000-100,000 mi

Symptoms: clunking when shifting into gear, excessive engine movement visible when revving in Park, vibration at idle that smooths out at speed, shifter feels loose or sloppy

Fix: Rubber mounts crack and separate, especially the front torque strut and transmission mount. These are straightforward replacements—1.5-2.5 hours total for both engine and trans mounts. Do them together as a set.

Estimated cost: $200-380

Symptoms: hard starting after sitting overnight, sputtering or hesitation under acceleration, stalling at idle after warmup, fuel pressure below spec (9-13 psi TBI system)

Fix: Old gasoline varnish clogs the in-tank sock filter and inline filter on TBI models. Filter replacement is 0.5 hours, but if the tank is contaminated, drop and clean adds 3-4 hours. Fuel pump replacement while tank is down is common insurance (add $150-250 parts).

Estimated cost: $180-550