1964 CADILLAC SEDAN DE VILLE

Typical onset: 80,000-120,000 mi

Symptoms: Delayed engagement into gear after 15-20 seconds when warm, Slipping between 2nd and 3rd gear under moderate throttle, Burnt transmission fluid smell and dark brown/black fluid, Loss of reverse or erratic shifting when fully warmed up

Fix: The TH400 runs hot in these heavy cars, especially with failed or clogged transmission oil coolers. Complete rebuild with updated clutch packs, new bushings, and mandatory oil cooler replacement/flushing takes 12-16 hours. If cooler wasn't maintained, metal debris circulates and destroys the fresh rebuild—always replace the cooler and flush all lines.

Estimated cost: $2,800-4,200

Typical onset: 120,000-180,000 mi

Symptoms: Deep knocking sound on cold start that quiets as oil pressure builds, Low oil pressure at idle (below 10 psi) on warm engine, Metallic ticking that worsens with RPM, especially under load, Bronze or copper flakes visible in drained oil

Fix: The 429 used soft Babbitt-type bearings that wear from infrequent oil changes and age-hardened oil passages. Full bottom-end rebuild with crank inspection/possible grinding, new main and rod bearings, fresh oil pump, and typically pistons/rings while you're in there. Engine must come out. Budget 35-45 hours for complete rebuild including removal/installation.

Estimated cost: $5,500-8,500

Typical onset: 90,000-150,000 mi

Symptoms: White smoke from exhaust on startup that clears after warmup, Coolant loss with no visible external leaks, Sweet smell from exhaust and milky residue on oil cap, Overheating under load or in traffic despite new thermostat/water pump

Fix: Original composite head gaskets deteriorate and the cork-rubber sections fail first. Both heads must come off for proper repair—never do just one side. Includes head resurfacing, new gaskets, fresh head bolts, and valve adjustment. While heads are off, expect to replace intake manifold gaskets too. 16-20 hours labor.

Estimated cost: $2,200-3,400

Typical onset: 70,000+ mi

Symptoms: Oil puddles under rear of engine after overnight parking, Oil dripping from bellhousing dust cover area, Oil consumption of 1 quart per 500-800 miles with no visible top-end leaks, Transmission fluid contaminated with engine oil (indicates severe rear seal failure)

Fix: These engines used rope-style rear main seals that harden and shrink with age. Transmission must be removed for access (8-10 hours labor). Modern conversion to neoprene lip seal is mandatory—rope seals no longer seal properly even when new. While transmission is out, replace transmission front pump seal and both transmission mounts.

Estimated cost: $1,400-2,100

Symptoms: Hard starting when engine is hot, starts fine cold, Rough idle with black smoke and fuel smell at idle, Engine dies when coming to a stop or flooding on attempted restart, Hesitation or flat spot during acceleration from cruise

Fix: The Carter AFB 4-barrel carburetors gum up from modern ethanol fuel and sitting. Needs complete disassembly, ultrasonic cleaning, new gaskets, float adjustment, accelerator pump replacement, and proper choke setup. Fuel filter element must be replaced and tank inspected for rust scale. If car sat more than 2 years, tank needs professional cleaning or replacement. 6-8 hours for full carburetor rebuild and fuel system service.

Estimated cost: $800-1,400

Typical onset: 60,000+ mi

Symptoms: Groaning noise when turning wheel at low speed or while parked, Power steering fluid puddles under front of car, Loose or wandering steering with constant correction needed, Hard steering when cold that improves as fluid warms up

Fix: Original seals in both the pump and steering gear box harden and leak. Pump rebuild with new seals and bearings takes 3-4 hours. Steering gear box typically needs complete replacement or professional rebuild—these aren't serviceable at shade-tree level. New gear box if available runs $600-900, rebuilt units $350-500. Add 4-6 hours labor for gear box replacement including alignment.

Estimated cost: $900-1,800