The 1979 Caprice is a body-on-frame B-body GM with solid bones but dated smog-era drivetrains. Common issues center around the TH350/TH200 transmissions, carburetor troubles, and typical big-car wear items magnified by weight and age.
TH200/TH350 Transmission Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: Slipping in 2nd gear or delayed engagement, No reverse or erratic shifting, Burnt transmission fluid smell, Clunking on deceleration from worn transmission mount
Fix: The TH200 (V6 cars) is weak and fails early; TH350s last longer but still need rebuilds or replacement by 120k. Expect 8-12 hours labor for R&R plus rebuild. Always replace the transmission oil cooler and lines while you're in there — corroded coolers cause repeat failures. Transmission mount replacement adds 1.5 hours.
Estimated cost: $1,800-3,200
Rochester Carburetor Issues (Dualjet/Quadrajet)
Common · medium severitySymptoms: Hard starting when warm, Rough idle and stalling at stops, Black smoke and poor fuel economy, Hesitation on acceleration
Fix: The Rochester 2-bbl (Dualjet on V6/small V8) and Quadrajet (305/350) suffer from deteriorated accelerator pump diaphragms, clogged jets, and warped throttle shafts after 40+ years. Professional rebuild runs 3-4 hours; many shops won't touch them anymore and suggest aftermarket replacements. DIY rebuild kits are $50-80 but require patience.
Estimated cost: $350-650
Engine Oil Consumption and Worn Piston Rings
Occasional · medium severityTypical onset: 100,000-180,000 mi
Symptoms: Blue smoke on startup or acceleration, Burning a quart every 500-800 miles, Fouled spark plugs, Low compression readings
Fix: Smog-era ring design and lackluster maintenance history means many need ring jobs or full rebuilds. Short block replacement is 16-22 hours depending on A/C and accessories; long block swap is similar. Many opt for used take-out engines given the car's value. Engine R&R alone is 12-14 hours on these.
Estimated cost: $2,800-5,500
Frame and Body Mount Rot
Occasional · high severitySymptoms: Body sag or separation at mount points, Creaking over bumps, Doors misaligned or hard to close, Visible rust perforation at rocker panels and frame rails
Fix: Rust-belt cars suffer frame rot at rear kick-up and around body mounts. Replacement body mounts (12 total) take 6-8 hours and require a lift. Frame section replacement is beyond most shops' scope. Inspect carefully before purchase — a rotted frame totals the car economically.
Estimated cost: $450-800
Fuel System Varnish and Clogged Filters
Common · low severitySymptoms: Sputtering at highway speeds, Stalling after sitting for weeks, Hard starting, Poor throttle response
Fix: Old gas turns to varnish in these if they sit. In-line fuel filter (0.3 hours) should be changed every year regardless of mileage. Fuel tank usually needs drop and cleaning (4-5 hours) if it's been sitting. Fuel pump (mechanical, on engine) fails occasionally — 1.5 hours to replace.
Estimated cost: $120-650
Rear Main Seal Oil Leak
Occasional · low severityTypical onset: 90,000+ mi
Symptoms: Oil drips from bell housing area, Oil spots on driveway centered under engine/trans junction, Transmission bellhousing wet with oil
Fix: Two-piece rear main seals were standard; they weep with age. Requires transmission removal (6-8 hours labor). Many live with a drip pan until doing a clutch or transmission job. Rope seal replacement adds 1-2 hours to any trans-out job.
Estimated cost: $450-750
Power Steering Pump and Hose Failure
Common · medium severityTypical onset: 70,000-130,000 mi
Symptoms: Whining or groaning when turning, Fluid leaks from pump or pressure hose, Stiff steering at low speeds, Pump pulley wobble
Fix: Saginaw pumps last well but seals harden. High-pressure hoses crack and leak at crimps. Pump replacement is 2 hours; pressure hose another 1.5 hours. Flush system when replacing pump to clear debris. Return hose is low pressure and cheap — do it preventively.
Estimated cost: $280-550
Buy one if the frame is solid and you can wrench or have a trusted indie shop — parts are cheap and plentiful, but you'll need them.
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.