1972 PONTIAC GTO

Typical onset: original units typically fail 80,000-120,000 mi, but most have unknown rebuild history

Symptoms: Slipping between gears, especially 1-2 shift, Delayed engagement into drive or reverse, Burnt transmission fluid smell, dark or metallic fluid, Loss of overdrive or stuck in second gear

Fix: Full rebuild required in most cases due to worn clutch packs, hardened seals, and valve body issues. 12-16 hours labor for R&R and rebuild. Many shops send these out, adding turnaround time. Includes new clutches, bands, seals, filter, and torque converter inspection.

Estimated cost: $1,800-3,200

Typical onset: varies wildly, but original engines showing issues 100,000+ mi, many sooner due to neglect

Symptoms: Heavy blue smoke on startup or acceleration indicating ring wear, Knocking or rod knock at idle, worse when warm, Low oil pressure below 10 PSI at hot idle, Excessive blowby from PCV system or oil filler cap

Fix: These Pontiac V8s are bulletproof when maintained but catastrophic when starved of oil or overheated. Short block replacement or in-frame rebuild needed: pull engine, disassemble, measure everything, replace bearings, rings, possibly pistons. Machine work for cylinder honing or boring adds cost. 25-35 hours labor for full rebuild including R&R.

Estimated cost: $4,500-8,000

Typical onset: not mileage-dependent, age and sitting are the killers

Symptoms: Hard starting when hot, stalling at idle after heat soak, Fuel smell in cabin or under hood, Rough idle, hesitation, or stumbling under acceleration, Visible fuel leaks at carb, fuel pump, or line connections

Fix: Original rubber fuel lines crack and collapse internally, steel lines rust through, and ethanol fuel destroys everything. Replace all fuel lines from tank to carb (2-4 hours), rebuild or replace mechanical fuel pump (1 hour), replace fuel filter, and often rebuild or replace the Rochester or Carter carburetor (3-5 hours). Tank cleaning or replacement often needed.

Estimated cost: $800-2,000

Symptoms: Visible rust perforation on frame rails near rear axle mounts, Cracking or separation at torque box areas, Sagging rear end or misaligned body panels, Control arm mounts showing rust-through or movement

Fix: A-body frames rust at rear spring mounts, torque boxes, and front subframe rails. Northern cars are often total losses. Repair requires cutting out bad sections and welding in new steel - 15-30 hours depending on extent. Some areas need full frame-off to access properly. This is a deal-breaker inspection point.

Estimated cost: $3,000-7,000

Typical onset: mounts fail every 40,000-60,000 mi, crossmember rust is age-related

Symptoms: Clunking when shifting into gear or on acceleration, Excessive driveline vibration at cruising speed, Transmission tail housing sitting low, visible sag, Harsh engagement into reverse

Fix: Rubber transmission mount deteriorates and the steel crossmember rusts through. Easy fix if caught early: 1-2 hours to drop crossmember and replace mount. If crossmember is rotted, replacement adds 2-3 hours and requires welding or bolt-in aftermarket piece.

Estimated cost: $200-600

Symptoms: Temperature creeping into 210-220°F range in traffic or summer heat, Coolant loss with no visible leaks, indicating internal head gasket weep, Steam from exhaust on cold start after sitting overnight, Heater performance poor or erratic

Fix: Original 2-row radiators barely adequate for emissions-era engines running warm. Add modern traffic and ethanol fuel heat issues and you're marginal. Re-core radiator or upgrade to 3-row (4-6 hours with proper flush), verify fan shroud present, check water pump and thermostat operation. Head gasket jobs on these run 12-16 hours labor.

Estimated cost: $600-2,500