1968 BUICK SPECIAL

Typical onset: 80,000-120,000 mi

Symptoms: Slipping between gears especially 1-2 shift, Delayed engagement when shifting into Drive, Burnt transmission fluid smell, No reverse or forward movement

Fix: Full rebuild required in most cases. These two-speed Powerglides and early TH350s weren't overbuilt and suffer clutch pack wear, torque converter issues, and valve body problems. Expect 12-16 hours labor for removal, rebuild, and reinstallation.

Estimated cost: $1,800-3,200

Typical onset: 60,000-90,000 mi

Symptoms: Severe knocking from bottom end, Metal shavings in oil, Sudden loss of oil pressure, Catastrophic engine seizure

Fix: The odd-fire 225 V6 has inherent harmonic vibration issues that destroy main bearings and can crack the crank. Requires complete engine teardown, crankshaft replacement or machining if salvageable, new bearings throughout. 18-24 hours labor. Most techs recommend swapping to a 350 V8 instead for similar cost.

Estimated cost: $2,500-4,000

Typical onset: 90,000-150,000 mi

Symptoms: Blue smoke on startup or acceleration, Burning through 1+ quart every 500-800 miles, Fouled spark plugs, Loss of compression on cylinder leak-down test

Fix: Ring wear accelerated by inadequate PCV ventilation and owners running non-detergent oils. Full ring job requires engine removal, honing cylinders, new rings on all pistons. If cylinders need boring, add piston replacement. 20-28 hours labor depending on accessibility and whether heads need work.

Estimated cost: $2,200-4,500

Symptoms: Loud clunk when shifting into gear, Excessive drivetrain vibration, Transmission visibly sagging when viewed from underneath, Harsh engagement

Fix: The rubber transmission crossmember mount deteriorates from heat and age. On these A-bodies you'll need to support the transmission with a jack, unbolt the crossmember, replace the mount. 1.5-2.5 hours labor. Inspect engine mounts at same time as they often fail together.

Estimated cost: $150-350

Symptoms: Hard starting especially when hot, Rough idle and stumbling, Fuel leaking from carburetor base, Engine flooding

Fix: Cars sitting for extended periods develop varnished carburetors (Rochester 2-barrel or 4-barrel depending on engine). Requires full carb rebuild with new gaskets, needle/seat, accelerator pump. Tank often has sediment requiring removal and cleaning, new fuel filter, lines flushed. 4-6 hours labor for thorough job.

Estimated cost: $400-800

Typical onset: 70,000-110,000 mi

Symptoms: Loud valve train clatter especially when cold, Loss of oil pressure at idle, Collapsed lifters, Wiped camshaft lobes

Fix: The 400 has marginal oiling to the top end, worsened by sludge buildup in oil galleys. Requires intake manifold removal, lifter replacement, often camshaft replacement if lobes are damaged. If oil galley plugs have failed, needs lower-end work. 12-18 hours labor depending on damage extent.

Estimated cost: $1,800-3,500