1977 BUICK LESABRE

Typical onset: 80,000-140,000 mi

Symptoms: Delayed engagement when shifting into drive or reverse, Slipping between gears, especially 1-2 shift, Burnt transmission fluid smell and dark/burnt fluid color, Transmission overheating in stop-and-go traffic or towing

Fix: These transmissions cook themselves when the factory cooler fails or gets clogged. Full rebuild requires 8-12 hours labor, includes new clutch packs, bands, seals, and filter. External cooler line replacement and adding auxiliary cooler strongly recommended to prevent repeat failure. Cooler lines rust through at the radiator connection points.

Estimated cost: $1,800-3,200

Typical onset: 120,000-180,000 mi

Symptoms: Deep knocking sound from bottom of engine, worse under load, Low oil pressure at idle (under 10 psi), Metallic debris in oil filter and pan, Sudden catastrophic failure if ignored

Fix: Main and rod bearings wear out from inadequate oil change intervals common with these cars. Requires full engine teardown, crank inspection/possible machining, new bearings, freeze plugs, and gaskets. 18-24 hours labor. If crank is damaged, core engine replacement or machine work adds cost. Many shops recommend short block or reman long block instead of rebuild due to age and unknown piston/cylinder wear.

Estimated cost: $3,500-6,500

Symptoms: Hard starting when hot, starts fine cold, Black smoke from exhaust, strong fuel smell, Flooding, gas dripping from carb throat, Rough idle, stalling at stop lights, Poor fuel economy (under 10 mpg)

Fix: Rubber components in the carb deteriorate with ethanol fuel and age. Needle/seat wears causing flooding. Proper rebuild with ethanol-resistant kit takes 2-3 hours, includes disassembly, cleaning, new gaskets, float adjustment, and proper choke setup. Many DIYers botch the adjustment causing more problems. Consider upgraded Edelbrock replacement for reliability.

Estimated cost: $350-650

Typical onset: 60,000-100,000 mi

Symptoms: Clunk when shifting from park to drive or reverse, Vibration through floorboard at idle in gear, Visible sagging or cracking of rubber mount, Excessive driveline movement felt during acceleration

Fix: The rubber transmission mount degrades and collapses allowing excessive movement. Simple replacement job at 1-1.5 hours labor with trans support and basic tools. Often ignored until it fails completely causing driveshaft angle issues and u-joint wear.

Estimated cost: $150-280

Symptoms: Stalling in hot weather after highway driving, Won't restart until engine cools down 20-30 minutes, Fuel smell in engine bay, Visible cracking or weeping rubber fuel lines

Fix: Original rubber fuel lines deteriorate and the mechanical fuel pump runs hot causing vapor lock with modern ethanol fuel. Replace all rubber fuel lines with proper fuel injection rated hose (2-3 hours), add heat shield to fuel pump and lines. Some owners install electric fuel pump to eliminate issue permanently.

Estimated cost: $400-750

Typical onset: 90,000-130,000 mi

Symptoms: Rattling noise from front of engine on cold start, Loss of power, poor acceleration, Check engine light (if equipped) or poor timing, Backfiring through carburetor, Catastrophic failure causes valve/piston contact

Fix: The Buick 3.8L odd-fire V6 timing chain stretches with wear and can jump teeth or break. Requires front cover removal, new chain, gears, and gaskets. 6-8 hours labor. Must be addressed when rattling starts or engine damage occurs. This engine is less desirable than the V8 options for this reason.

Estimated cost: $800-1,400