The 1973 Caprice is a full-size BOF cruiser built on GM's B-body platform with solid small-block reliability but notorious TH350/TH400 transmission vulnerabilities and carburetor emissions-era tuning headaches. These are tanks when maintained but suffer from deferred maintenance neglect typical of older low-value vehicles.
TH350/TH400 Transmission Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: Delayed engagement into drive or reverse, Slipping between 1-2 or 2-3 shifts under load, Burnt transmission fluid smell and dark/metallic fluid, No movement in any gear after transmission overheating
Fix: Full rebuild required in most cases due to worn clutch packs, bands, and sun shell damage. TH350 rebuild takes 8-12 hours including R&R, TH400 slightly more. Transmission cooler lines and radiator cooler should be flushed/replaced simultaneously to prevent recontamination.
Estimated cost: $1,800-3,200
Quadrajet Carburetor Issues
Common · medium severitySymptoms: Rough idle and stalling when cold, especially after sitting, Black smoke from tailpipe and fuel smell indicating rich condition, Hesitation or flat spot on acceleration from stop, High fuel consumption beyond the expected 10-12 mpg
Fix: Rochester Quadrajet carbs suffer from deteriorated float needles, accelerator pump diaphragms, and plugged idle circuits from ethanol fuel. Professional rebuild with modern gasket kit takes 3-4 hours. Many owners botch DIY adjustments making it worse—this needs someone who knows Q-jets.
Estimated cost: $400-750
Lower Engine Wear (350/400/454)
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: Loud rod knock at idle that increases with RPM, Heavy blue smoke on startup and deceleration, Oil pressure dropping below 10 psi at hot idle, Metal contamination visible in oil filter during changes
Fix: Worn main and rod bearings are common on neglected oil changes or overheating events. Short block replacement is most economical (16-20 hours labor). Full rebuilds with machine work run 25-35 hours. The 350 is cheapest to rebuild, 454 parts cost significantly more. Piston ring wear alone is rare—usually bearings fail first.
Estimated cost: $2,800-5,500
Frame Rust and Body Mount Deterioration
Common · high severitySymptoms: Visible rust perforation on frame rails behind front wheels, Body sag or misalignment with doors not closing properly, Clunking over bumps from collapsed body mounts, Steering wander from spring pocket or steering box mount rust
Fix: Salt-belt cars have serious frame rust issues in shock tower areas, spring pockets, and rear trailing arm mounts. Body mounts rot out leaving rubber bonded to metal remnants. Body mount replacement alone is 6-8 hours. Frame repair requires welding and fabrication—not DIY territory. Southern/Western cars avoid this almost entirely.
Estimated cost: $800-1,500 body mounts only; $3,000+ frame welding
Power Steering Gear Box Leaks
Common · low severityTypical onset: 60,000-100,000 mi
Symptoms: Power steering fluid dripping from steering box onto frame, Groaning noise when turning at low speeds, Increased steering effort when fluid level drops, Visible seepage around sector shaft seal
Fix: Saginaw rotary valve steering boxes develop input shaft and sector shaft seal leaks. Rebuilt boxes are readily available and swap takes 2-3 hours including alignment check. Seal replacement alone isn't worth it—labor equals box R&R time anyway. Keep fluid topped to avoid pump damage.
Estimated cost: $350-600
Fuel System Varnish and Tank Contamination
Occasional · medium severitySymptoms: Engine dies after 15-20 minutes of driving when tank is below half, Difficulty starting after sitting for days or weeks, Fuel filter clogs repeatedly within 500-1000 miles, Visible rust particles or sludge in fuel filter
Fix: Cars sitting for extended periods develop varnish in tank and fuel lines. Sock filter in tank disintegrates. Requires tank removal and professional cleaning/sealing or replacement (4-5 hours), new sending unit, fuel lines flushed, and inline filter. Mechanical fuel pump diaphragms also fail from ethanol—replace preventively.
Estimated cost: $600-1,100
Buy a rust-free Southern example with documented maintenance—avoid neglected Northern cars unless you're prepared for frame work that costs more than the car's worth.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.