1957 CADILLAC SEDAN DE VILLE

Symptoms: Slipping between 2nd and 3rd gear under load, Delayed engagement into Drive or Reverse (more than 2-3 seconds), Harsh or banging shifts, especially when cold, Complete loss of forward gears but Reverse still works

Fix: Full rebuild required in nearly all cases—internal clutch packs, bands, and seals are degraded from age regardless of mileage. Transmission must come out (8-12 hours removal/reinstall), then rebuild with correct friction materials. Original-spec parts are NLA; require specialized Hydra-Matic rebuilder. Oil cooler lines typically replaced simultaneously as they're brittle.

Estimated cost: $3,500-6,500

Typical onset: 80,000-120,000 mi

Symptoms: Heavy knocking on startup that lessens when warm (rod bearings), Low oil pressure at idle below 10 psi hot, Metallic debris on magnetic drain plug, Sudden catastrophic knock followed by seizure

Fix: Age-hardened oil passages and decades of wear mandate full crankshaft removal, machine work (journal polishing or grinding .010-.020 undersize), and new bearings. Plan on 24-32 shop hours for proper bottom-end overhaul with engine out. Often find crankshaft needs grinding, connecting rods need resizing. While it's apart, expect to do cam bearings, timing chain, and oil pump.

Estimated cost: $5,000-8,000

Symptoms: White smoke on startup that clears after 30 seconds (valve seals), Coolant loss with no visible leaks, sweet smell from exhaust, Oil in coolant or milky appearance on dipstick, Rough idle, misfiring on one or more cylinders

Fix: Head gaskets fail from age and thermal cycling; original composition gaskets don't hold up. Both heads off (18-24 hours), resurface mandatory as they warp over decades. Valve guides wear oversize—bronze guide liners required, valve job essential. Most shops doing one head do both preventively. Expect hardened valve seats installed if running unleaded fuel.

Estimated cost: $3,200-5,500

Symptoms: Hard starting when cold, requires multiple cranking cycles, Stumbling or dying when coming off idle, Flooding, raw fuel smell, black smoke, Idle speed hunts between 400-900 RPM

Fix: Carter WCFB four-barrel carburetors on these gum up from ethanol fuel and sitting. Full disassembly, ultrasonic cleaning, new gaskets/seals, and proper float adjustment required (6-8 hours for thorough job). Fuel pump diaphragms harden—replacement mandatory. Steel fuel lines rust internally; flushing or replacement needed. Inline filter alone won't fix this.

Estimated cost: $800-1,500

Typical onset: 70,000-100,000 mi

Symptoms: Excessive blue smoke under acceleration, High oil consumption (1 quart per 500 miles or worse), Loss of compression, sluggish acceleration, Positive crankcase pressure, oil pushed out breather

Fix: Rings lose tension with age even at low miles. If cylinder bores aren't scored, can get by with ring replacement and hone (engine out, 20-26 hours). However, if bores are worn .005+ or tapered, needs full bore and oversize pistons. At this age, most engines need the full treatment. Often combined with bottom-end work since it's already apart.

Estimated cost: $4,000-7,500

Symptoms: Clunk when shifting from Park to Drive or Reverse, Excessive driveline vibration at 45-55 mph, Visible sagging of transmission tailshaft, Exhaust contact or scraping noises over bumps

Fix: Original rubber mounts are 65+ years old and completely hardened or crumbled. Transmission sits too low, causes driveline angles to change, wears U-joints prematurely. Replacement requires supporting transmission, unbolting crossmember (3-5 hours). NOS or reproduction mounts available but verify quality—some repros are too soft.

Estimated cost: $400-750