1979 PONTIAC LEMANS

Typical onset: 70,000-110,000 mi

Symptoms: slipping between gears especially 1-2 shift, delayed engagement when shifting to drive, whining noise in gear, no forward gears but reverse works

Fix: The TH200 (metric 200) was GM's weakest automatic and grenades regularly behind even the small V8s. Rebuild requires 8-12 hours, but most shops recommend swapping to a TH350 from a heavier LeMans or similar A-body which adds fabrication time for crossmember and driveshaft work. Core TH200 rebuild is 10-14 hours labor.

Estimated cost: $1,400-2,200

Typical onset: 60,000-140,000 mi

Symptoms: rough idle and stalling when warm, black smoke on acceleration, hesitation off idle, high fuel consumption, won't pass emissions

Fix: The Rochester Quadrajet needs full rebuild kits by now — accelerator pump worn, power piston springs collapsed, float needles sticking. Combined with cracked vacuum lines to EGR, AIR pump, and EVAP systems. Carb rebuild is 3-4 hours, chasing vacuum leaks adds another 2-3 hours of diagnostic time.

Estimated cost: $450-850

Typical onset: 90,000-150,000 mi

Symptoms: knocking sound on cold start that quiets when warm, low oil pressure at idle, metallic rattling under load, milky oil from coolant intrusion on some

Fix: The Pontiac 301 and Chevy 305 especially see spun rod bearings from marginal oil pressure and worn cam bearings. Olds 403 eats main bearings. Full bearing replacement requires engine pull, hot tank, crank polish — 18-24 hours labor. Often becomes full rebuild when you're that deep.

Estimated cost: $2,800-4,500

Typical onset: 80,000-120,000 mi

Symptoms: coolant loss with no visible leak, white smoke on startup, rough idle, oil looks milky or chocolate pudding texture

Fix: The composite intake gaskets fail from heat cycling, leaking coolant into cylinders or oil passages. Pontiac and Olds V8s worse than Chevy units. Requires manifold removal, careful deck surface cleaning, new gaskets and sometimes valley pan. 5-7 hours labor including coolant flush.

Estimated cost: $550-900

Typical onset: 100,000+ mi

Symptoms: oil drips from bellhousing area, wet spots under car after sitting, oil consumption without visible valve cover leaks

Fix: Two-piece rope seals leak as they age and dry out. Proper fix requires transmission removal for access — 8-10 hours labor. Many owners live with it and keep a drip pan underneath since the leak is usually slow. Speedi-Sleeve conversion recommended during replacement.

Estimated cost: $650-1,100

Symptoms: clunking over bumps, body shifting relative to frame, visible rust perforation near rear spring mounts, doors misaligned

Fix: Northeastern and rust-belt cars see serious frame rail rot ahead of rear axle and at body mount points. Body bushings disintegrate from age. Inspection critical before purchase — frame repairs require welding and plating (12-20 hours), body mounts are 4-6 hours. Structural integrity issue.

Estimated cost: $800-2,500