1975 CADILLAC DEVILLE

Typical onset: 80,000-150,000 mi

Symptoms: Heavy knocking from crankcase especially on cold start, Rapidly dropping oil pressure, Metal shavings in oil filter, Sudden oil consumption increase

Fix: Main bearings spin due to inadequate oiling at idle and debris buildup in oil passages. Requires complete tear-down, crank grinding (usually .010 or .020 under), new bearings, rod inspection, and often a full short block replacement if neglected. 18-24 labor hours for short block swap, 28-35 hours for complete rebuild in-frame.

Estimated cost: $3,500-6,500

Typical onset: 60,000-120,000 mi

Symptoms: Pink milkshake in radiator overflow, Transmission slipping when hot, Leaking cooler lines at crimp fittings, Burnt ATF smell

Fix: Steel cooler lines rot at bends and crimp points; internal radiator cooler can rupture mixing coolant and ATF. Requires new cooler lines (3-4 hours), often radiator replacement or external cooler add-on (6-8 hours total), complete fluid flush, and if contamination occurred, transmission rebuild (12-16 hours).

Estimated cost: $800-4,200

Typical onset: 70,000-130,000 mi

Symptoms: Blue smoke on deceleration and startup, Fouled spark plugs, 1 quart per 500-800 miles consumption, Carbon buildup on valves

Fix: Low-tension rings from emission-era design combined with cylinder wash from rich carb tuning. Proper fix is top-end overhaul with hone and new rings (14-18 hours) or full rebuild if cylinders are scored. Band-aid: heavier oil (20W-50) and frequent top-ups.

Estimated cost: $2,200-3,800

Symptoms: Black smoke and fuel smell, Hesitation on acceleration, Hard starting when hot, Gas puddling in intake manifold

Fix: Float needles wear, secondaries stick, accelerator pump diaphragms crack. Rebuild kit with careful float adjustment takes 3-4 hours. Most shops just swap on a refurbished unit (1.5 hours). Ignore and you'll wash cylinders leading to ring problems.

Estimated cost: $250-650

Typical onset: all mileages

Symptoms: Clunk when shifting D to R, Excessive driveline vibration, Transmission tail visible sagging, Harsh engagement

Fix: Rubber mounts deteriorate from age and oil saturation. Replacement requires transmission support, 2-3 hours labor. Often discovered during transmission service. Letting it go damages the tailshaft housing and crossmember.

Estimated cost: $180-350

Symptoms: Stalling in hot weather after short trips, Won't restart until engine cools 20-30 minutes, Rough idle when heat-soaked, Fuel pump clicking but not pumping

Fix: Fuel lines routed too close to exhaust manifolds, mechanical pump heat-soak on block. Add heat shield to pump (1 hour), reroute fuel lines away from exhaust (2-3 hours), or install low-pressure electric pump (3-4 hours). Ethanol fuel makes it worse.

Estimated cost: $150-550