1979 BUICK SKYLARK

Typical onset: 60,000-90,000 mi

Symptoms: Slipping between 1st and 2nd gear under moderate throttle, Delayed engagement into Drive or Reverse, Transmission fluid appearing burnt or metallic on dipstick, Complete loss of forward gears with only Reverse working

Fix: The metric TH200 automatic behind many 231 V6 engines was chronically weak from the factory. Internal clutch pack and intermediate band failure is typical. Rebuilds require 8-12 hours labor, but most shops recommend replacing with a TH350 swap for longevity (adds 4-6 hours for crossmember and driveshaft modifications). Fluid and cooler line work is routine maintenance but won't prevent the inevitable.

Estimated cost: $1,800-3,200

Typical onset: 80,000-120,000 mi

Symptoms: Heavy knocking sound from lower engine block that worsens with RPM, Metal shavings or glitter visible in oil during changes, Oil pressure dropping below 10 psi at idle when warm, Sudden catastrophic engine seizure in severe cases

Fix: The Buick 3.8L V6 had a reputation for crankshaft walking and wiping out main bearings, especially in engines with deferred oil changes. Repair requires full engine teardown—20-28 hours labor for crank R&R plus machine work for journal grinding. Most techs recommend sourcing a running used engine or rebuilding with the block out of the car. Short block replacement runs 18-24 hours.

Estimated cost: $2,800-4,800

Symptoms: Rough idle and stalling when cold, runs fine when fully warm, Black smoke and fuel smell from exhaust under acceleration, Hesitation or flat spot when pressing throttle from stop, Poor fuel economy—dropping below 12 mpg city

Fix: Late-70s emission carburetors are nightmares of vacuum lines, tamper-proof idle screws, and failing choke pull-offs. The Rochester Dualjet and Varajet models common on the 231 V6 develop leaking power valves and worn throttle shafts. Full rebuilds take 4-6 hours including tuning; most independent shops swap for remanufactured units (2-3 hours). Aftermarket Edelbrock conversions are popular but require removing smog equipment.

Estimated cost: $450-950

Typical onset: all ages affected

Symptoms: Visible gaps between body and frame along rocker panels, Clunking or creaking sounds over bumps that seem to come from underneath, Doors that suddenly don't close properly or require slamming, Sagging or wavy body panels near quarter windows

Fix: Salt-belt Skylarks rot aggressively at body mount points and rear frame rails behind the axle. Rubber body mounts collapse by 40 years regardless of mileage. Replacing all 12 mounts takes 6-8 hours with a lift. Frame rust requires sectioning and welding—estimate 12-20 hours if doing it right. Surface rust is manageable; structural perforation means walk away.

Estimated cost: $850-3,500

Symptoms: Engine stumbling or dying in hot weather after extended idling or slow traffic, Hard starting when engine is heat-soaked after shutdown, Fuel smell inside cabin or visible wetness along frame rails, Engine running lean with hesitation despite carburetor appearing correct

Fix: Steel fuel lines rust through along the frame, especially near the fuel filter and pump. Vapor lock from fuel boiling in the lines is common in summer—the mechanical fuel pump sits right on the hot block. Replacing corroded lines from tank to engine runs 4-6 hours. Adding an electric fuel pump and return line (popular fix) takes 3-4 hours. Fuel filter changes are 30-minute jobs but often reveal larger issues.

Estimated cost: $350-850

Typical onset: 100,000+ mi

Symptoms: Blue smoke on startup or during deceleration, Oil consumption exceeding 1 quart per 500-800 miles, Fouled spark plugs on one or more cylinders, Poor compression readings below 100 psi on multiple cylinders

Fix: Ring seal deteriorates from carbon buildup and wear. Both the 231 V6 and Olds 260 V8 burn oil excessively past 100k. Ring replacement alone requires engine removal and full teardown—24-30 hours labor. Most shops recommend full rebuild with pistons, bearings, and machine work at this point. Top-end only jobs (heads and valves) run 14-18 hours but don't solve ring issues.

Estimated cost: $2,200-4,200