1981 BUICK CENTURY

Typical onset: 80,000-130,000 mi

Symptoms: Slipping between gears, especially 2nd to 3rd, Delayed engagement when shifting into drive, Whining or grinding noises under acceleration, Transmission fluid dark and burned-smelling

Fix: These lightweight transmissions weren't built for longevity. Complete rebuild with updated clutch packs and bands runs 12-16 hours labor. Many shops recommend the 200-4R swap over rebuilding a TH200C.

Estimated cost: $1,800-3,200

Typical onset: 60,000-100,000 mi

Symptoms: White smoke from exhaust on startup, Loss of coolant with no external leaks, Hard starting when warm, Sudden loss of power and heavy knocking

Fix: The Olds 350 diesel is notorious for head gasket failures, cracked heads, and failed injection pumps. Head studs pull out of the block. Rebuild requires machining and proper studs, 25-35 hours. Many owners swap to a gas 305 or 350 instead (20-25 hours).

Estimated cost: $4,500-7,000

Typical onset: 70,000-110,000 mi

Symptoms: Excessive engine movement during acceleration, Clunking when shifting into gear, Vibration through floorboard at idle, Difficulty shifting manual transmission if equipped

Fix: Rubber mounts deteriorate and separate. Transmission mount is a common failure point causing harsh shifts. Engine mounts run 2-3 hours, transmission mount 1.5-2 hours. Replace all three at once.

Estimated cost: $350-600

Symptoms: Rough idle and stalling when cold, Hesitation on acceleration, Black smoke from exhaust, Poor fuel economy (under 12 mpg city)

Fix: Rochester Quadrajet carbs develop vacuum leaks, worn throttle shafts, and stuck choke mechanisms. Rebuilds run 3-4 hours but often need repeated adjustment. Ethanol fuel accelerates deterioration of gaskets and diaphragms.

Estimated cost: $400-750

Typical onset: 90,000-150,000 mi

Symptoms: Oil puddles under rear of engine, Oil spots on driveway after sitting overnight, Low oil level between changes, Oil coating on transmission bellhousing

Fix: Two-piece rear main seals are prone to leaking. Rear seal requires transmission removal, 8-10 hours. Oil pan gasket is simpler at 3-4 hours but access is tight. Often done together if transmission is already out.

Estimated cost: $600-1,400

Symptoms: Stalling after sitting for weeks, Difficulty starting after fillup, Loss of power under load, Surging at highway speeds

Fix: Ethanol fuel leaves varnish in carburetors and clogs inline fuel filters quickly. Filter replacement is 0.5 hours, but carburetor cleaning adds 2-3 hours. Tanks often have rust sediment requiring drop and clean (4-5 hours).

Estimated cost: $150-650

Typical onset: 80,000-120,000 mi

Symptoms: Sweet coolant smell in cabin, Fogged windshield that's oily to touch, Overheating in traffic, Coolant loss with no visible external leaks

Fix: Original hoses crack and burst. Heater core failure is common and requires dash removal, 6-8 hours labor. Lower radiator hoses collapse internally causing overheating. Replace all hoses preventively.

Estimated cost: $450-900