1956 CADILLAC SERIES 62

Typical onset: 60,000-90,000 mi

Symptoms: Slipping between gears, especially 2nd to 3rd, Delayed engagement when shifting to Drive, Harsh or banging shifts, Transmission overheating, burning smell

Fix: The four-speed Hydra-Matic is notorious for worn clutch packs and failed oil pump seals. Full rebuild requires 16-20 hours labor, often needs new bands, clutches, seals, and sometimes the oil cooler lines. Cooler itself frequently leaks and should be replaced during rebuild.

Estimated cost: $3,500-5,500

Symptoms: Hard starting when hot, Fuel smell in garage, visible leaks from carb base, Rough idle, stalling at stop lights, Black smoke from exhaust, poor fuel economy

Fix: The Carter WCFB four-barrel is complex with multiple gaskets, floats, and accelerator pump components that deteriorate. Rebuild kits are available but proper setup requires 4-6 hours for someone experienced with these units. Ethanol fuel accelerates gasket failure.

Estimated cost: $600-1,200

Typical onset: 70,000-120,000 mi

Symptoms: Oil puddles under rear of engine, Oil coating on bell housing and transmission, Low oil level warnings, burning oil smell, Blue smoke on startup

Fix: The rope-style rear main seal hardens with age and requires transmission removal to replace—12-16 hours labor. Valve cover gaskets and oil pan gaskets also leak frequently but are easier fixes at 3-4 hours combined.

Estimated cost: $1,800-3,200

Typical onset: 80,000-130,000 mi

Symptoms: White smoke from exhaust, Coolant in oil, milky dipstick, Overheating, bubbling in radiator, Loss of coolant with no visible leaks

Fix: The 331 can blow head gaskets between cylinders or into water jackets, especially if overheated. Requires 18-24 hours for both heads, includes resurfacing, new gaskets, and typically new head bolts. Often discover cracked heads during disassembly on high-mileage engines.

Estimated cost: $2,800-4,500

Symptoms: Overheating in traffic or on hills, Radiator leaks at seams or tank joints, Water pump wobble or squealing, Heater core leaks, coolant smell in cabin

Fix: Original radiators are brass/copper and often need re-coring or replacement (8-10 hours with removal). Water pump rebuilds take 3-4 hours. Heater cores are difficult—dashboard removal required, 12-15 hours. Rubber hoses deteriorate and should all be replaced as preventive maintenance.

Estimated cost: $800-2,500

Typical onset: 60,000-100,000 mi

Symptoms: Clunk when shifting into gear, Vibration at highway speeds, Excessive driveline movement visible under throttle, Transmission appears to sag

Fix: Rubber transmission mount deteriorates and allows excessive movement. Replacement is straightforward at 2-3 hours, but while in there, check U-joints and carrier bearing. Driveshaft balance is often off on original shafts.

Estimated cost: $400-800

Symptoms: Misfiring at idle or under load, Hard starting, Rough running, loss of power, Backfiring through carburetor

Fix: Points-type ignition requires maintenance every 10,000-12,000 miles. Distributor shaft bushings wear causing timing instability—rebuild takes 4-6 hours with proper equipment. Consider electronic ignition conversion for reliability, adds 3-4 hours to initial setup.

Estimated cost: $300-900