1978 CHEVROLET CAPRICE

Typical onset: 80,000-150,000 mi

Symptoms: Burnt transmission fluid smell, dark or varnished ATF, Slipping or delayed engagement when hot, Coolant in transmission pan or ATF in radiator overflow, Leaking steel cooler lines at frame or radiator connections

Fix: Factory cooler routing through the radiator often leads to cross-contamination when the internal separator fails. External cooler retrofit plus fresh cooler lines is mandatory. Transmission rebuild typically needed if coolant intrusion occurred. Labor: 12-18 hours for full rebuild, 3-4 hours for cooler lines and external cooler install only.

Estimated cost: $1,800-3,200

Symptoms: Flooding or fuel dripping from airhorn after shutdown, Hesitation or stumble on acceleration from stop, Hard starting when hot, smooth when cold, Raw fuel smell in garage after sitting overnight

Fix: Rochester Quadrajet carbs on these vintage small-blocks suffer from deteriorated float needle seats and hardened accelerator pump cups. Aftermarket rebuild kits widely available. Complete rebuild and adjustment takes 2-3 hours for someone familiar with Q-jets, longer if choke adjustment or vacuum secondaries need tuning.

Estimated cost: $350-650

Typical onset: 100,000-180,000 mi

Symptoms: Oil accumulation on garage floor after overnight parking, Oil wetness at bell housing or oil pan rails, Visible drips from rear of engine during inspection, Clutch contamination (if rare manual transmission equipped)

Fix: Two-piece rear main seals on these Gen I small-blocks leak as rope seal compresses over time. Oil pan gaskets fail from repeated heat cycles and cork degradation. Rear main requires transmission removal; budget 8-10 hours. Oil pan can sometimes be done in-chassis (4-5 hours) but exhaust and crossmember often complicate access.

Estimated cost: $800-1,400

Typical onset: 60,000-120,000 mi

Symptoms: Clunking when shifting into Drive or Reverse, Excessive engine shake at idle in gear, Visible engine tilt or sagging when hood is open, Vibration through floor at highway speeds

Fix: Rubber mounts harden and crack with age, causing drivetrain movement. Replacement is straightforward: jack engine slightly, unbolt old mounts, install new. Both engine mounts plus transmission mount should be done together. Labor: 2-3 hours for all three mounts.

Estimated cost: $300-500

Symptoms: Visible rust perforation at body mount points, Sagging rear end or uneven ride height, Cracking sound over bumps from body shifting on frame, Body misalignment or door fit issues

Fix: Rust-belt cars suffer badly at rear spring pockets and forward body mounts where moisture traps. Inspect carefully before purchase—surface rust is fine, but structural perforation requires welding or frame section replacement. Repair ranges from patch welding (4-6 hours) to full frame rail replacement (20+ hours).

Estimated cost: $600-4,000

Symptoms: Fuel gauge reading erratic or stuck on empty/full, Fuel odor near rear of vehicle, Visible corrosion or weeping at tank seams, Fuel starvation or stumbling when tank below half

Fix: Forty-plus-year-old steel tanks rust from inside out, especially if car sat for years with ethanol fuel. Sending unit floats collapse or corrode. Tank replacement requires dropping exhaust and supporting rear axle. Labor: 3-4 hours for sending unit only, 5-6 hours for full tank replacement.

Estimated cost: $400-900

Symptoms: No-start condition, cranks but won't fire, Intermittent stalling when engine is hot, Tachometer drops to zero during failure event, No spark at plugs confirmed with timing light

Fix: HEI distributor ignition modules fail from heat buildup, especially on V8s in hot climates. Pickup coil under rotor degrades with thermal cycling. Both parts are cheap and easy to replace: 1 hour labor max. Carry spares if relying on the car for daily transport.

Estimated cost: $150-300