1974 PONTIAC BONNEVILLE

Typical onset: 80,000-130,000 mi

Symptoms: Delayed engagement when shifting into gear, Slipping between 2nd and 3rd gear under load, Burnt transmission fluid smell, Metal shavings in pan during fluid change

Fix: Transmission oil cooler lines rot out or cooler itself clogs, starving fluid flow. This cooks clutch packs and seals. Full rebuild requires 12-16 hours labor, includes new clutches, bands, seals, and cooler/lines replacement. Cooler-only jobs run 3-4 hours if caught early.

Estimated cost: $1,800-3,200

Symptoms: Black smoke on acceleration, Rough idle and stumbling, Spark plugs carbon-fouled every 5,000 miles, Poor fuel economy (under 8 mpg city)

Fix: The Rochester Quadrajet carbs on '74s run rich from the factory due to emissions tuning, and float needles wear fast. Ethanol gas accelerates deterioration. Proper rebuild with modern gaskets, careful float adjustment, and jets tuned for today's fuel takes 4-6 hours. Many shops slap kits in without proper calibration.

Estimated cost: $450-800

Typical onset: 60,000-100,000 mi

Symptoms: Loud ticking or tapping from valve covers at startup, Noise persists after warmup, Loss of power and rough running, Low oil pressure at idle

Fix: Pre-1988 engines built for high-zinc oil; modern oils starve the flat-tappet camshaft and lifters. Camshaft lobes wear, lifters collapse. Requires intake manifold removal, new cam, lifters, timing set. On Pontiac V8s this is 14-18 hours labor because of accessory packaging. Many engines get a full rebuild at this point due to worn rings.

Estimated cost: $2,200-4,500

Symptoms: Visible rust perforation near body mounts, Clunking over bumps from loose subframe, Cracked or separated frame rails at stress points, Control arm mounts tearing from frame

Fix: B-body frames rust through at body mount pockets and front subframe attachment points. Repair requires frame-off or partial frame work, welding in plates or replacement sections. Labor-intensive: 20-40 hours depending on extent. Many cars are totaled at this point due to value vs. repair cost.

Estimated cost: $3,500-8,000

Typical onset: 70,000-120,000 mi

Symptoms: Whining noise when turning at low speeds, Power steering fluid puddles under car, Stiff steering when cold, Low fluid level despite topping off

Fix: Saginaw power steering pumps leak from shaft seals, gearboxes leak from sector shaft seals. Pump replacement is 2 hours, gearbox rebuild or replacement is 4-6 hours due to steering linkage disconnection. OEM-quality parts still available. Flush system to prevent contamination damage.

Estimated cost: $350-900

Typical onset: 90,000-150,000 mi

Symptoms: Blue smoke on startup or acceleration, Oil consumption 1 quart per 500-1,000 miles, Fouled spark plugs on multiple cylinders, Low compression readings across cylinders

Fix: Piston rings wear from heat cycling and poor oil maintenance. Pontiac V8s with factory-weak ring tension suffer more. Requires engine teardown: piston/ring replacement is 18-22 hours, often combined with valve job. Many owners opt for reman long block at this point (20-24 hours R&R).

Estimated cost: $3,200-5,500