1978 BUICK CENTURY

Typical onset: 60,000-90,000 mi

Symptoms: White smoke from exhaust, Coolant contamination in oil (milky dipstick), Loss of compression, Sudden no-start with seized engine, Metal shavings in oil

Fix: GM's 5.7L diesel used gasoline-engine-based block with inadequate head bolts and weak main caps. Head gasket failures cascade into block cracking. Repair requires complete engine replacement or rebuild with extensive machine work. Expect 25-35 hours for R&R plus machine shop time and parts.

Estimated cost: $4,500-8,000

Typical onset: 70,000-120,000 mi

Symptoms: Clunking on acceleration/deceleration, Excessive driveline vibration, Visible sag of transmission tailshaft, Difficulty shifting into gear

Fix: Rubber transmission mounts deteriorate and separate, allowing excessive drivetrain movement. Common across all A-body cars with TH200/TH350. Simple replacement takes 1.5-2 hours on a lift with exhaust work sometimes needed for access.

Estimated cost: $150-300

Typical onset: 80,000-150,000 mi

Symptoms: Transmission fluid spots under car, Low fluid level on dipstick, Rust staining at radiator connections, Slipping or delayed engagement when fluid gets low

Fix: Steel cooler lines rust through at bends and radiator connections, especially in salt states. Replacement lines are cheap but routing through frame and crossmember takes 2-3 hours. Must refill and check for proper shifting afterward.

Estimated cost: $200-400

Typical onset: 120,000-180,000 mi

Symptoms: Deep knocking noise from bottom end, Low oil pressure at idle, Metal particles in oil filter, Gradual power loss

Fix: The Buick 231 V6 (3.8L) can develop main bearing wear, especially if oil changes were neglected. Requires complete teardown, crank grinding/replacement, and new bearings. Short block replacement often more cost-effective than full rebuild. Engine R&R plus machine work: 18-25 hours total.

Estimated cost: $2,800-4,500

Symptoms: Hard starting when cold, Rough idle and stalling, Black smoke or hesitation on acceleration, Poor fuel economy

Fix: Ethanol fuel gums up the Rochester 2GC/2GE carburetors on gas engines after sitting or with irregular use. Usually needs complete rebuild with new jets, gaskets, and accelerator pump. DIY-friendly but finicky to tune. Professional rebuild: 2-3 hours.

Estimated cost: $250-450

Symptoms: Doors misalign or don't close properly, Visible rust through at rocker panels, Body sags or leans, Floor pan holes visible from underneath

Fix: A-bodies in salt states rot at body mounts, frame rails behind front wheels, and floor pans. Body mount replacement requires lifting body off frame (12-16 hours). Frame section welding is specialized work. Inspect before purchase—uneconomical to repair on low-value cars.

Estimated cost: $1,500-3,500