1986 PONTIAC 6000

Typical onset: 60,000-90,000 mi

Symptoms: coolant loss with no visible external leak, white smoke from exhaust on cold start, rough idle when warmed up, oil looks milky or foamy on dipstick

Fix: Lower intake gaskets leak coolant into crankcase or combustion chambers. Requires intake removal, gasket set, resurfacing if warped. 4-6 hours labor. Often find corroded coolant passages requiring additional cleaning.

Estimated cost: $450-750

Typical onset: 80,000-120,000 mi

Symptoms: slipping between 1st and 2nd gear, delayed engagement into drive or reverse, whining noise that changes with vehicle speed, no movement in any gear (complete failure)

Fix: This 3-speed automatic is notoriously weak—governor gear strips, throttle valve sticks, clutch packs burn. Rebuild requires 8-12 hours plus parts. Many shops recommend replacement over rebuild due to repeat failures. Fluid and filter changes every 30k can help but won't prevent eventual failure.

Estimated cost: $1,200-2,200

Typical onset: 90,000-130,000 mi

Symptoms: persistent overheating despite new thermostat and radiator flush, combustion gases in coolant (bubbling in reservoir), coolant push-out from reservoir cap, loss of power under load

Fix: Head gaskets fail from age and cooling system neglect. Both heads need removal, resurfacing, new gaskets, timing set inspection. 10-14 hours labor. Often cascades from intake gasket leaks that went too long. Check for warped heads—common on this engine.

Estimated cost: $1,400-2,000

Typical onset: 70,000-110,000 mi

Symptoms: excessive vibration at idle in gear, clunking when shifting from park to drive, engine visibly rocks when revved in park, steering wheel vibration at stoplights

Fix: Hydraulic engine mounts collapse, especially on passenger side. Transmission mount also common. Each mount 1.5-2.5 hours depending on access. Do all three at once if one is bad—labor overlap saves money.

Estimated cost: $300-550

Symptoms: hard starting when engine is hot, stalling at idle after warmup, surging at steady throttle, black smoke and poor fuel economy

Fix: Early '86 models may have Rochester E2SE carburetor—mixture control solenoid fails, choke pull-off sticks, accelerator pump wears. Rebuild kits available but many techs swap to junkyard TBI setup from later models. Carb rebuild 3-4 hours if you can find someone who still does them.

Estimated cost: $250-500

Typical onset: 80,000-140,000 mi

Symptoms: intermittent no-start when hot, random stalling while driving, bucking and misfiring under load, starts fine when cold, dies after 20 minutes

Fix: HEI distributor ignition module fails from heat. Module replaceable in 30-45 minutes, but often the entire pickup coil assembly is also worn. Distributor cap and rotor should be replaced simultaneously—carbon tracking is common. Module alone $80-120 parts, 0.5-1 hour labor.

Estimated cost: $150-300