The 1982 Bonneville sits on GM's rear-drive B-body platform with multiple V6/V8 options and a THM200-4R or THM350C transmission. Most problems stem from carburetor-era fuel delivery, aging TH200-4R automatics, and typical G-body rubber/bushings degradation after 40+ years.
TH200-4R Transmission Failure (4-speed overdrive models)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Slipping between 2nd and 3rd gear under load, No 4th gear overdrive engagement or drops out on highway, Burned ATF smell, dark red or brown fluid, Clunking into reverse or delayed engagement
Fix: TH200-4R has weak direct clutch drum and input shaft. Rebuild requires hardened parts upgrade, converter replacement, and valve body work. 8-12 hours labor plus parts.
Estimated cost: $1,800-2,800
Quadrajet Carburetor Fuel Delivery Issues
Common · medium severitySymptoms: Hard starting when hot, requires pumping pedal, Hesitation or stumble on acceleration from stop, Black smoke at idle or cruise, fouled plugs, High idle or hunting RPM when warm
Fix: Quadrajet secondary air valve sticking, accelerator pump worn, or float needle leaking. Full rebuild kit plus carb removal/cleaning runs 3-5 hours. Many shops just swap for remanufactured unit.
Estimated cost: $400-750
305/350 Olds Diesel Engine Catastrophic Failure (if diesel-equipped)
Occasional · high severityTypical onset: 60,000-120,000 mi
Symptoms: White smoke on cold start that doesn't clear, Loss of power, excessive blowby, Coolant consumption without external leaks, Sudden loud knocking followed by shutdown
Fix: GM's 5.7L diesel has weak head bolts causing head gasket failure and cracked blocks. Most owners swap to gas V8 rather than rebuild. Engine R&R plus conversion 18-25 hours.
Estimated cost: $3,500-6,000
Rochester Fuel Pump and Sender Unit Failure
Common · medium severityTypical onset: 100,000+ mi
Symptoms: Stalling when fuel tank below 1/4 full, Engine dies after 15-20 minutes driving, restarts when cool, Fuel gauge reads empty or pegged full regardless of level, Whining noise from tank area
Fix: In-tank pump on some models or mechanical pump with weak diaphragm. Tank drop required for sender/pump combo. 2-4 hours labor depending on rust and line condition.
Estimated cost: $350-650
Rear Main Seal and Oil Pan Gasket Leaks
Common · low severityTypical onset: 70,000+ mi
Symptoms: Large oil spot after overnight parking, centered under bellhousing, Oil dripping from transmission bellhousing seam, Oil consumption 1 quart per 500-800 miles without visible exhaust smoke, Oil coating back of starter and flexplate
Fix: Two-piece rear main seal design leaks as rope seal hardens. Transmission must come out. Oil pan gasket cork deteriorates. Combined job 6-9 hours depending on exhaust/crossmember access.
Estimated cost: $800-1,400
Computer Command Control (CCC) System Faults
Occasional · medium severitySymptoms: Check engine light stays on, surging at steady throttle, Won't pass emissions despite fresh tune-up, Oxygen sensor codes, mixture too rich or lean, Intermittent stalling with no pattern
Fix: Early ECM and sensor failures common with 40-year-old electronics. Diagnostic time-consuming without proper scanner. O2 sensor, ECM, and wiring harness shorts most common. 2-5 hours diagnosis plus repair.
Estimated cost: $300-900
Front Suspension Bushings and Ball Joints
Common · medium severityTypical onset: 60,000-90,000 mi
Symptoms: Clunking over bumps from front end, Wandering steering, requires constant correction, Tire wear on inside or outside edges, Steering wheel shimmy 45-60 mph
Fix: Control arm bushings, upper/lower ball joints, and idler arm wear out. Full front end rebuild with alignment runs 6-8 hours. Rusted hardware adds time.
Estimated cost: $900-1,600
Buy a gas V8 model with documented transmission service; avoid diesels entirely and budget $2k first year for deferred maintenance on any survivor.
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.