1966 BUICK SPECIAL

Typical onset: 60,000-90,000 mi

Symptoms: Deep knocking sound from bottom end especially under load, Loss of oil pressure, Metal shavings in oil, Severe vibration that worsens with RPM

Fix: The 90-degree odd-fire V6 has inherent imbalance causing crankshaft and main bearing premature wear. Requires full engine teardown, crank inspection/replacement, main and rod bearing replacement. Often discover cracked block webbing. 18-24 hours labor for in-car rebuild, 28-35 hours for full R&R and rebuild or block replacement.

Estimated cost: $2,800-5,500

Typical onset: 70,000-110,000 mi

Symptoms: Delayed engagement when shifting to drive, Slipping between gears especially when hot, Burnt transmission fluid smell, No movement in any gear after overheating episode

Fix: The two-speed automatic has marginal cooling capacity and the factory cooler often clogs or leaks. Trans mounts fail allowing excessive movement. Overheating destroys clutch packs and seals. Requires transmission R&R, rebuild with upgraded clutches, new cooler and lines, and mount replacement. 12-16 hours labor.

Estimated cost: $1,800-3,200

Typical onset: 80,000-120,000 mi

Symptoms: Blue smoke on startup and acceleration, Excessive oil consumption (1 quart per 500-800 miles), Fouled spark plugs, Loss of compression, Poor fuel economy

Fix: Ring technology and cylinder wall finish of this era led to accelerated wear. Requires cylinder honing, new rings on all pistons, valve job while in there. Can sometimes get by with in-car ring job if cylinders aren't tapered badly. 20-26 hours for proper teardown, measure, hone, reassemble.

Estimated cost: $1,600-3,000

Typical onset: 90,000-140,000 mi

Symptoms: Rattling noise from front of engine on cold start, Erratic idle, Backfiring through carburetor, Check timing and it keeps changing, Hard starting when engine is hot

Fix: Nylon cam gear teeth shed material, timing chain stretches excessively. Retarded cam timing causes running issues and can lead to valve-piston contact if gear fails completely. Front cover removal, timing set replacement, oil pump inspection. 8-12 hours labor.

Estimated cost: $800-1,400

Symptoms: Stalling in hot weather after shutdown then restart, Hesitation and stumbling when hot, Hard starting when engine is warm, Runs fine when cold, terrible when heat-soaked

Fix: Fuel pump mounted on engine block heat-soaks fuel, lines run too close to exhaust manifolds. Rochester carburetors need frequent rebuild with ethanol fuel. Install heat shield, reroute fuel lines away from heat, rebuild or replace carburetor, electric fuel pump conversion helps. 4-6 hours for comprehensive fix.

Estimated cost: $400-900

Symptoms: Clunking over bumps from front end, Visible rust perforation in frame rails, Steering feels loose or wandering, Door alignment issues that worsen, Sagging front end

Fix: Box frame construction traps moisture and salt, rusts from inside out. Front subframe mounts rot allowing movement. Inspection reveals rust jacking and perforation that isn't visible externally. Repair requires frame section replacement or reinforcement plating, subframe bushing replacement. 16-24 hours depending on severity, often not economically viable.

Estimated cost: $2,500-6,000