The 1987 Pontiac 6000 is a GM A-body with typical front-wheel-drive GM reliability of the era — decent bones but plagued by transmission failures, intake manifold gasket leaks on the 2.8L V6, and various cooling system problems that often escalate into engine damage if ignored.
TH125/TH440-T4 Automatic Transmission Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: delayed engagement into gear, slipping between 2nd and 3rd, whining or grinding noises, burnt transmission fluid smell, no reverse or intermittent reverse
Fix: These 3-speed automatics are notoriously weak, especially with the V6. Rebuild typically takes 8-12 hours including R&R, converter replacement, and band/clutch pack overhaul. Many shops recommend replacing the external oil cooler lines and adding an auxiliary cooler during the job.
Estimated cost: $1,800-2,800
2.8L V6 Intake Manifold Gasket Failure
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: coolant loss with no visible leak, white smoke at startup, rough idle when warm, coolant in oil (milky dipstick), overheating
Fix: The composite gaskets deteriorate and allow coolant into the intake ports or oil passages. Job requires manifold removal, new gaskets, thermostat, and often coolant hoses while you're in there. Plan 5-7 hours labor. Critical to check for head gasket damage if it's been overheated.
Estimated cost: $600-1,000
Engine Overheating Leading to Head Gasket or Engine Failure
Occasional · high severityTypical onset: 90,000-150,000 mi
Symptoms: persistent overheating, coolant mixing with oil, white exhaust smoke, loss of compression, external coolant leaks at head/block junction
Fix: Often a cascade failure starting with intake gaskets or a failed water pump. If ignored, leads to warped heads or cracked blocks. Head gasket job alone is 10-14 hours; if the block is damaged you're looking at a junkyard engine swap or rebuild. Pistons, rings, bearings all get replaced in a full rebuild.
Estimated cost: $1,500-4,500
Crankshaft Position Sensor and Ignition Module Failures
Occasional · high severitySymptoms: no-start condition, cranks but won't fire, stalling when hot, restarts when cool, intermittent dying while driving, no spark at plugs
Fix: The ignition module (mounted on distributor or coil pack depending on year) fails when heat-soaked. Crank sensor can also cause identical symptoms. Diagnosis takes 1-2 hours if you're chasing intermittent faults. Parts are cheap but misdiagnosis wastes time and money.
Estimated cost: $200-500
Front Engine and Transmission Mounts Deterioration
Common · low severityTypical onset: 70,000-120,000 mi
Symptoms: clunking when shifting into drive or reverse, excessive engine movement visible under hood, vibration at idle, difficulty shifting smoothly
Fix: Rubber mounts collapse over time, especially the front torque strut. Replacing all three mounts (engine, transmission, torque strut) takes about 3-4 hours. Not dangerous but accelerates wear on CV axles and exhaust hangers.
Estimated cost: $300-600
Fuel System Corrosion and Filter Clogging
Occasional · medium severityTypical onset: 100,000+ mi
Symptoms: hard starting, stumbling or hesitation under load, stalling, check engine light with lean codes
Fix: Steel fuel lines rust from the inside out, shedding debris into the filter and injectors. Filter should be changed every 30k but rarely is. Injector cleaning may help temporarily; corroded lines require replacement which involves lifting the car and tracing lines from tank to engine — 4-6 hours.
Estimated cost: $400-900
Only buy if it's well-documented, low miles, and cheap — these are mechanic's specials that nickel-and-dime you into a transmission or engine job.
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.