1972 CHEVROLET BEL AIR

Typical onset: 90,000-140,000 mi

Symptoms: Slipping between gears especially 1-2 shift, Delayed engagement when shifting to Drive, Burnt transmission fluid smell, Metal shavings in pan during fluid changes

Fix: These GM automatics fail predictably from worn clutch packs, hardened seals, and valve body wear. Full rebuild takes 8-12 hours including R&R. Most shops pull the trans rather than attempt in-car work. Torque converter replacement adds 1-2 hours and $200-400. Original units often have 100k+ on them now, many on second or third rebuilds.

Estimated cost: $1,800-3,200

Typical onset: 120,000-180,000 mi

Symptoms: Heavy knocking from crankcase especially when cold, Oil pressure drops below 10 psi at idle when hot, Metallic debris in oil filter, Visible connecting rod through oil pan in catastrophic cases

Fix: Main and rod bearings wear from decades of heat cycling and inconsistent oil changes. The 350 V8 especially suffers spun bearings at high mileage. Proper fix requires full teardown with crank inspection/machining, new bearings, and often new oil pump. In-frame rebuild is 16-24 hours labor. Most owners at this point opt for reman long block or crate engine instead of machining original block. Pistons and rings typically need replacement during any bottom-end work due to ring land wear and carbon buildup.

Estimated cost: $3,500-6,500

Symptoms: Loud clunk when shifting from Park to Drive or Reverse, Excessive vibration at idle in gear, Transmission tail housing drooping visibly, Driveline angle issues causing U-joint wear

Fix: Original rubber mounts turn to powder after 50 years regardless of mileage. Crossmember also rusts through on cars from salt states. Replacement is straightforward - support trans with jack, remove 4-6 bolts, swap mount. Takes 1-2 hours. Always inspect crossmember for rust perforation while you're under there. Poly mounts available as upgrade but transmit more vibration.

Estimated cost: $150-350

Symptoms: Hard starting especially after sitting, Rough idle and stumbling on acceleration, Flooding or fuel smell in garage, Black smoke from tailpipe indicating rich condition

Fix: Rochester and Quadrajet carbs on these cars suffer from ethanol-degraded gaskets, stuck float needles, and varnished passages. Rebuild kits run $50-80 but proper rebuild takes 3-4 hours including removal, disassembly, cleaning, and tuning. Most techs also replace fuel filter and check fuel pump while they're in there. In-tank sending units often fail simultaneously requiring tank drop (add 2-3 hours). Modern ethanol fuel accelerates deterioration so cars sitting more than 6 months typically need carb work.

Estimated cost: $400-800

Symptoms: Coolant dripping from bell housing area, Unexplained coolant loss without external leaks, Steam from engine bay after shutdown, Coolant in oil pan in severe cases

Fix: Steel freeze plugs corrode from inside-out especially on the rear cylinder bank plugs near the bellhousing. Rear plugs require transmission removal to access properly - 6-8 hours total labor. Smart move is replacing all 8-10 plugs once you're in there since others will fail soon. Water pump leaks are also common at 40+ years but are easy 2-hour jobs. Heater core failure is frequent but more labor intensive requiring dash removal.

Estimated cost: $600-1,400

Symptoms: Visible rust perforation on frame rails especially behind front wheels, Body sitting unevenly or sagging, Creaking sounds over bumps, Doors not closing properly due to body flex

Fix: Box-frame construction on these B-bodies traps moisture and road salt. Critical inspection points are front crossmember, rear spring mounts, and rocker panel frame sections. Surface rust is manageable with wire wheel and POR-15, but perforation requires welding in patch panels or frame sections. Body mounts (rubber biscuits) turn to mush and need replacement every 20-30 years regardless of mileage. Full body-off restoration to address frame properly is 40+ hours but most shops do rolling repairs as sections fail. Non-salt-state cars fare much better.

Estimated cost: $800-3,500