1970 PONTIAC TEMPEST

Typical onset: 80,000-120,000 mi

Symptoms: slipping between gears especially 1-2 shift, delayed engagement when shifting to drive, burnt transmission fluid smell, whining or grinding noise in gear

Fix: Full rebuild required in most cases—clutch packs, bands, seals, filter, converter inspection. Expect 12-16 hours labor for a proper rebuild with machine work. These units weren't built for modern stop-and-go abuse.

Estimated cost: $1,800-3,200

Typical onset: 100,000-150,000 mi

Symptoms: excessive oil consumption (more than 1 qt per 500 miles), blue smoke on startup or acceleration, low compression across multiple cylinders, knocking or rattling from bottom end, metal shavings in oil

Fix: The 326 and 389 V8s from this era need rings, main bearings, and rod bearings at this age. If cylinders are scored, expect a bore and oversize pistons. Full tear-down is 25-35 hours including machine shop time for hot tank, magnaflux, bore/hone. The I6 is simpler but parts are harder to source.

Estimated cost: $3,500-6,500

Typical onset: 120,000+ mi

Symptoms: severe knocking that worsens with RPM, metallic grinding at idle, low oil pressure despite fresh oil, vibration through entire vehicle

Fix: Catastrophic bottom-end failure usually from deferred maintenance or oil starvation. Requires full engine pull, crankshaft removal, inspection for scoring or out-of-round journals. If crank needs grinding or replacement, add machine shop time. Total 30-40 hours with R&R.

Estimated cost: $4,000-7,000

Symptoms: clunking when shifting into gear, excessive driveline vibration, visible sagging of transmission tail, rubber mount split or separated from metal

Fix: Original rubber mounts are 50+ years old and turn to dust. Crossmember often rusts through in salt states. Mount replacement is 2-3 hours, but if crossmember needs welding or replacement, add another 4-6 hours. Inspect thoroughly during any transmission work.

Estimated cost: $250-800

Symptoms: red fluid pooling under vehicle, transmission overheating, low fluid level requiring frequent top-ups, corroded or cracked steel lines at fittings

Fix: Factory steel lines rust through, especially at crimp points and radiator connections. Replacement lines are 3-4 hours including making custom bends if originals aren't available. Also check the cooler itself inside the radiator—internal leaks will mix coolant and ATF, destroying the transmission.

Estimated cost: $300-600

Symptoms: hard starting after sitting, stalling at idle or under load, surging or hesitation during acceleration, fuel odor from deteriorated rubber lines

Fix: Modern ethanol fuel eats original rubber lines and leaves varnish deposits in carb, pump, and tank. Full system service includes tank cleaning or replacement, new fuel pump, carburetor rebuild, and rubber line replacement. 8-12 hours if tank needs to come out.

Estimated cost: $800-1,500