1972 AMC HORNET

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between gears, especially 1st to 2nd, Delayed engagement when shifting to Drive or Reverse, Burned transmission fluid smell, dark or metallic fluid, No forward movement but reverse works (front clutch failure)

Fix: The Borg-Warner automatic (Torque Command) used in these develops clutch pack and bushing wear. Rebuild requires 12-16 hours including R&R. Original cooler lines rust through causing fluid loss and overheating—replace proactively. External cooler addition recommended during rebuild.

Estimated cost: $1,800-3,200

Typical onset: 90,000-150,000 mi

Symptoms: Coolant consumption with no visible leaks, White smoke from exhaust on cold start, Oil milkshake (coolant mixing with oil), Overheating under load or in traffic

Fix: The 232 and 258 I6 engines blow head gaskets between cylinders 3-4 or into the cooling passages. Job takes 8-10 hours including head milling (almost always warped). Check for cracked head while off—common if previously overheated. Timing chain replacement recommended while in there.

Estimated cost: $1,200-1,800

Typical onset: 100,000-180,000 mi

Symptoms: Clunking when engaging clutch (manual) or shifting into gear (auto), Excessive crankshaft endplay—can feel movement pushing clutch pedal, Metallic knocking that changes with clutch operation, Eventually causes oil pressure drop and catastrophic failure

Fix: The I6 thrust bearing (center main) wears from clutch riding or torque converter issues pushing crank forward. Requires full engine teardown, crank removal for inspection/possible grinding, and main bearing replacement. 20-28 hours labor for proper job. If neglected, crank journals get damaged requiring replacement or welding/machining.

Estimated cost: $2,200-4,000

Symptoms: Hard starting when hot, floods easily when cold, Rough idle, stalling at stop signs, Fuel leaking from carburetor base or accelerator pump, Poor fuel economy (under 12 mpg city on I6)

Fix: Carter or Motorcraft carbs on these sit unused for years, developing varnish and dried seals. Tank often has rust sediment clogging inline filter and sock. Full carb rebuild kit plus tank cleaning/sealing takes 6-8 hours. Fuel pump (mechanical) often weak—replace simultaneously. Ethanol fuel accelerates degradation.

Estimated cost: $600-1,100

Typical onset: 60,000-120,000 mi

Symptoms: Excessive vibration at idle in Drive, Clunking when accelerating or lifting off throttle, Visible engine movement when revving in Park, Shifter vibration, difficult gear engagement

Fix: Rubber mounts disintegrate from age and oil saturation. Transmission mount (crossmember style) most critical—allows tailshaft to drop and bind shifter linkage. All three motor mounts plus transmission mount should be done together, 3-4 hours labor. Cheap insurance against drivetrain damage.

Estimated cost: $400-650

Symptoms: Overheating in traffic or on hills, Coolant leaks from freeze plugs or heater core, Radiator tanks separated from core (solder joints fail), Rusty coolant, clogged radiator passages

Fix: Original radiators are 50+ years old—cores plugged with sediment, tanks leaking. Freeze plugs rust through from inside out (common on barn finds). Water pump impellers corrode away. Budget for complete cooling refresh: radiator recore or replacement, all hoses, thermostat, water pump, flush block. 6-9 hours depending on freeze plug work.

Estimated cost: $800-1,500

Typical onset: 120,000-200,000 mi

Symptoms: Blue smoke on deceleration or startup, High oil consumption (quart per 500-800 miles), Weak compression across multiple cylinders, Excessive crankcase pressure, oil pushed out breather

Fix: High-mileage survivors develop ring and cylinder wear—AMC I6 bores aren't as durable as Chevy or Ford. Short block overhaul requires honing or boring, new pistons/rings, bearings. 24-32 hours for proper in-car rebuild. Many shops recommend pulling engine for access. Consider full rebuild if main bearings also worn.

Estimated cost: $2,800-5,000