1973 CADILLAC FLEETWOOD SIXTY SPECIAL

Typical onset: 120,000-180,000 mi

Symptoms: deep knocking from bottom end especially under load, oil pressure dropping dramatically, metallic debris in oil filter, severe vibration at idle

Fix: Complete engine teardown required. Crankshaft needs grinding or replacement, main bearings replaced, line boring often needed. Expect 25-35 hours labor plus machine shop time. Many shops won't tackle it—easier to find running 472 core and swap.

Estimated cost: $4,500-7,500

Typical onset: 50+ years old regardless of miles

Symptoms: transmission fluid puddles under front of car, pink fluid dripping near radiator, low transmission fluid warnings, burnt smell if run low too long

Fix: Steel cooler lines rust through where they mount to radiator or at frame contact points. Fabricate new lines or source NOS—reproduction quality is hit-or-miss. 2-4 hours depending on line routing complexity. Check radiator end tank cooler for mixing with coolant.

Estimated cost: $350-650

Typical onset: 100,000-150,000 mi

Symptoms: blue smoke on startup and deceleration, consuming 1+ quarts between changes, fouled spark plugs, loss of power on highway grades, excessive crankcase pressure

Fix: Worn piston rings from years of idling and short trips. Full teardown—hone cylinders, replace rings, often pistons too if skirt wear present. Ridge reaming critical on these blocks. 30-40 hours labor. Many opt for complete rebuild at this point given age.

Estimated cost: $3,500-5,500

Symptoms: clunk when shifting into drive or reverse, excessive driveline vibration at 40-50 mph, visible sagging of transmission tail, banging noise over bumps from underneath

Fix: Rubber mounts disintegrate after 50 years. Jack transmission, replace mount—straightforward but heavy components. 1.5-2.5 hours. Do both engine mounts at same time if original—they're likely shot too.

Estimated cost: $200-400

Symptoms: hard starting when hot, raw fuel smell in engine bay, black smoke at idle, stalling after sitting in traffic, gas puddles on intake manifold

Fix: Rochester Quadrajet needs rebuild—needle/seat wear and heat soak issues common. Rebuild kit plus 3-4 hours for proper calibration. Consider heat shield improvements. Fuel filter plugging from tank rust accelerates carburetor wear—replace filter first.

Estimated cost: $400-750

Symptoms: pedal slowly sinking to floor when held at stop, reduced braking power, fluid level dropping in reservoir with no visible leaks, pedal feels spongy after bleeding

Fix: Internal seals deteriorate—especially on cars that sat. Master cylinder rebuild or replacement plus full system bleed. 2-3 hours. Inspect all wheel cylinders and brake hoses while you're in there—they're original too.

Estimated cost: $300-550