The 1964 Buick LeSabre with the 300ci V8 and two-speed automatic is a solid cruiser hampered by aging transmission technology and typical wear on 60-year-old engine internals. Most issues stem from deferred maintenance and parts availability rather than fundamental design flaws.
Two-Speed Automatic (ST-300) Transmission Failure
Common · high severityTypical onset: original units often fail between 80,000-120,000 mi without rebuilds
Symptoms: Slipping between 1st and 2nd gear under load, Delayed engagement when shifting into Drive, Transmission fluid leaking from cooler lines or pan gasket, Harsh or no upshift above 40 mph
Fix: Full rebuild required in most cases — clutch packs, bands, seals, and often the oil cooler lines are corroded through. Expect 12-16 hours labor for R&R and rebuild. Parts availability is fair but expect delays on specialty internals.
Estimated cost: $1,800-3,200
Lower End Bearing Wear and Oil Pressure Loss
Common · high severityTypical onset: manifests around 100,000+ mi if oil changes were inconsistent
Symptoms: Oil pressure drops below 10 psi at hot idle, Knocking or rumbling from crankcase at startup, Metal flakes in oil during changes, Warning light flickers during deceleration
Fix: Requires full teardown — main bearings and often rod bearings are worn beyond spec. Many shops opt for short block replacement if machining is needed. Budget 24-30 hours labor for full lower-end rebuild including crank polishing.
Estimated cost: $3,500-5,500
Piston Ring Blowby and Compression Loss
Occasional · medium severityTypical onset: typically 90,000-140,000 mi on original rings
Symptoms: Blue smoke on startup that clears after warm-up, Excessive crankcase pressure venting from breather, Oil consumption above 1 quart per 500 miles, Poor cold-start performance
Fix: Rings can be replaced without full rebuild if cylinder walls measure within spec (hone and re-ring). Otherwise budget for bore and oversized pistons. 18-22 hours labor for heads-off ring job.
Estimated cost: $2,200-3,800
Head Gasket Failure Between Cylinders
Occasional · medium severityTypical onset: not strictly mileage-driven — often from overheating or improper torque on prior work
Symptoms: Coolant in oil (milky dipstick), White smoke from exhaust continuous during operation, Combustion gases bubbling into radiator, Misfires on adjacent cylinders
Fix: Heads must come off for inspection and milling if warped. Original composite gaskets fail more than modern replacements. 10-14 hours labor for both heads R&R and surface prep.
Estimated cost: $1,400-2,400
Fuel System Varnish and Carburetor Gumming
Common · low severitySymptoms: Hard starting after sitting overnight, Stumble or flat spot during acceleration, Idle hangs high then drops suddenly, Fuel smell from evaporating varnish in bowl
Fix: Full carburetor rebuild with ultrasonic cleaning, new fuel filter, and tank inspection. If car sat for years, tank likely has rust scale. 4-6 hours labor for carb overhaul; add 3-4 hours if tank needs drop and coat.
Estimated cost: $450-900
Transmission Mount and Crossmember Deterioration
Common · low severityTypical onset: rubber mounts harden and crack by 50,000-70,000 mi or 40+ years age
Symptoms: Clunk when shifting from Park to Drive, Vibration felt through floor at idle in gear, Transmission appears to sag visually from underneath, Exhaust rattles against crossmember under load
Fix: Replace rubber mount and inspect crossmember for rust-through. Often combined with transmission service since access is similar. 2-3 hours labor.
Estimated cost: $250-500
Buy one if it has service records proving regular fluid changes and recent transmission work — otherwise budget $4,000-6,000 for deferred powertrain catch-up within the first year.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.