1979 BUICK ELECTRA

Typical onset: 60,000-100,000 mi

Symptoms: White smoke from exhaust indicating coolant intrusion, Cracked cylinder heads from inadequate bolting, Sudden loss of compression across multiple cylinders, Fuel in coolant or coolant in oil

Fix: The Oldsmobile-built 350 diesel is fundamentally flawed with weak head bolts, inadequate block casting, and fuel system issues. Most require complete engine replacement or conversion to gas V8. Rebuilds rarely last. Expect 40-60 hours labor for engine swap including all ancillaries, wiring, and exhaust modifications.

Estimated cost: $4,500-8,000

Typical onset: 80,000-150,000 mi

Symptoms: Transmission fluid in radiator appearing as pink milky coolant, Coolant in transmission causing delayed engagement or slipping, Rusted or leaking steel cooler lines at radiator fittings, Transmission overheating after coolant mixes with ATF

Fix: Steel cooler lines rust through where they connect to the radiator, allowing coolant and ATF to mix. Requires radiator removal and flushing, replacement of all cooler lines, transmission fluid flush (sometimes multiple times), and often transmission rebuild if contamination was severe. Plan 8-12 hours for full repair with transmission service, 25-35 hours if rebuild needed.

Estimated cost: $800-1,200 for lines/flush, $2,200-3,500 with rebuild

Typical onset: 100,000-140,000 mi

Symptoms: Slipping between 1st and 2nd gear under load, Delayed engagement when shifting from Park to Drive, No 3rd gear or stuck in 2nd gear indicating governor issues, Clunking into reverse with worn direct clutches

Fix: Both the TH350 (V6/small V8) and TH400 (big block) transmissions wear clutch packs and seals predictably. The TH350 is particularly prone to 2nd gear band adjustment issues and servo leaks. Full rebuild with torque converter replacement takes 12-16 hours. Hard parts rarely fail, so rebuild is usually successful long-term.

Estimated cost: $1,800-2,800

Typical onset: 70,000-120,000 mi

Symptoms: Excessive engine movement visible during acceleration/deceleration, Clunking when shifting into gear, Vibration at idle that worsens with AC on, Hood contact marks from engine rising under load

Fix: The rubber deteriorates and the liquid-filled mounts collapse, especially on the heavier 350 V8 models. Transmission mount fails first typically, then motor mounts. All three should be replaced together. Requires engine support and exhaust disconnection. Figure 4-6 hours for all mounts.

Estimated cost: $450-750

Symptoms: Hard starting when hot (heat soak percolation), Black smoke and flooding from stuck float or needle valve, Stumble on acceleration from accelerator pump failure, High idle or hunting idle from vacuum leaks in secondary side

Fix: The Rochester Quadrajet is rebuildable but requires expertise. Most common issues are brass float developing pinhole leaks (sinks), stuck power piston in primary metering rods, and deteriorated secondary air valve dashpot. Quality rebuild takes 3-4 hours including removal, bench work, and proper adjustment. Many shops just replace with remanufactured unit.

Estimated cost: $350-650 rebuild, $450-800 reman

Typical onset: 90,000-150,000 mi

Symptoms: Oil puddle centered under bellhousing area, Oil coating bottom of transmission bellhousing, Gradual oil consumption requiring 1 quart per 800-1,000 miles

Fix: Two-piece rear main seal design leaks as rope seal hardens and shrinks. Oil pan gasket also weeps from cork degradation. Rear main requires transmission removal: 8-10 hours labor. Oil pan on V8 models requires removing motor mounts and jacking engine due to crossmember clearance: 4-5 hours. Do both together if possible.

Estimated cost: $650-1,100 for both