1974 CHEVROLET CAPRICE

Typical onset: 50,000-150,000 mi

Symptoms: Hard starting when hot, needs multiple cranking attempts, Black smoke on acceleration, fuel smell in garage, Stumbling or flat spots during acceleration, Gas mileage drops below 10 mpg even for the 350

Fix: The Rochester Quadrajet needs complete rebuild with proper float adjustment and accelerator pump calibration. Critical to set float level precisely—too high floods the engine. Includes new needle/seat, gaskets, and pump diaphragm. 3-4 hours for experienced carb tech, double that if you've never done one.

Estimated cost: $350-650

Typical onset: 80,000-120,000 mi

Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration through floorboard at highway speed, Transmission tailshaft sitting visibly low, Exhaust system contact noise over bumps

Fix: The rubber transmission mount deteriorates and allows excessive drivetrain movement that cracks the crossmember. Cannot just replace the mount—must inspect crossmember carefully and often replace or reinforce it. Requires transmission support during work. 4-6 hours including crossmember reinforcement or replacement.

Estimated cost: $450-900

Typical onset: 100,000-180,000 mi

Symptoms: Blue smoke on startup that clears after warmup, Using 1+ quart every 500-800 miles, Low compression readings (under 120 psi) but not catastrophically low, Oily residue in air cleaner housing

Fix: The smog-era tuning runs these engines rich and cool, causing cylinder glazing and premature ring wear. A proper fix requires hot-tank deglazing, new rings, ridge reaming, and valve job while you're there. Many shade-tree mechanics try re-ringing without deglazing and waste their money. 18-24 hours for complete in-frame overhaul with heads off.

Estimated cost: $2,200-3,800

Symptoms: Body sits crooked or leans to one side, Visible rust perforation where leaf spring mounts to frame, Doors won't close properly after years of closing fine, Cracking paint on rear quarter panels from frame flexing

Fix: These frames trap moisture at the rear spring pockets and body mount locations. Surface rust is manageable, but once perforated you're looking at frame section replacement or boxing reinforcements welded in. Common in snow-belt cars but happens everywhere eventually. Proper fix requires body-off-frame or extensive jacking/support. 12-20 hours depending on extent.

Estimated cost: $1,800-4,500

Typical onset: 60,000-120,000 mi

Symptoms: Transmission fluid in coolant (pink or brown milkshake in radiator), Coolant in transmission (strawberry milkshake on dipstick), Transmission shifting erratically after highway drives, Rusty steel cooler lines weeping at radiator connections

Fix: The internal transmission cooler in the radiator develops pinhole leaks allowing fluid mixing. Once contaminated, transmission internals are toast—the glycol destroys clutches and seals. Requires radiator replacement, new cooler lines, transmission flush and filter, often full rebuild if driven after mixing. 8-12 hours for radiator/lines/flush, add 20+ hours if trans rebuild needed.

Estimated cost: $800-1,200 (if caught early), $2,500-4,000 (if trans damaged)

Symptoms: Engine pings under light load despite running premium fuel, Rough idle that smooths at higher RPM, Poor fuel economy and sluggish acceleration, Won't pass emissions even when properly tuned

Fix: The factory timing specs are retarded for emissions, creating pinging and poor performance. Points wear causes timing drift. Most owners convert to HEI electronic ignition from later models and advance timing 4-6 degrees beyond factory spec. Includes distributor swap, wiring modification. 2-3 hours for competent DIY-er.

Estimated cost: $180-400