1982 OLDSMOBILE 98

Typical onset: 60,000-100,000 mi

Symptoms: white smoke from exhaust, coolant loss without external leaks, hard starting when warm, milky oil on dipstick, sudden loss of compression

Fix: Head gasket failure due to inadequate head bolt torque from factory leads to coolant intrusion and hydro-lock. Proper fix requires ARP studs, milled heads, and updated gaskets—4-6 hours labor if caught early. Most owners face complete engine replacement (12-16 hours) because damage is discovered too late. Many swap to gas 350.

Estimated cost: $3,500-7,500

Typical onset: 80,000-130,000 mi

Symptoms: slipping on 2-3 shift, no overdrive engagement, delayed engagement when cold, burnt fluid smell, shuddering under light throttle

Fix: The 200-4R overdrive unit behind the 307/350 gas engines has weak direct clutches and pump wear. Band adjustments help temporarily but rebuild is inevitable. Expect 8-10 hours for R&R plus rebuild. Torque converter often needs replacement simultaneously.

Estimated cost: $1,800-2,800

Typical onset: 90,000-150,000 mi

Symptoms: rattling from front of engine on cold start, rough idle that smooths after warmup, check engine light with timing-related codes, loss of power, backfiring through intake

Fix: Nylon cam gear teeth wear and timing chain stretches, causing retarded cam timing. Replace chain, gears, and front seal while you're in there—5-7 hours labor. Critical on the 307 and 350 gas engines. Diesel uses gear drive, not affected.

Estimated cost: $650-1,100

Symptoms: no start condition, stalling after warmup, loss of power under load, extended cranking before start, runs fine then suddenly dies

Fix: The diesel injection pump develops internal wear and fuel solenoid failures. Rebuilds are scarce and expensive, used pumps are a gamble. 3-4 hours labor for replacement. This is a terminal diagnosis for most diesel 98s.

Estimated cost: $1,200-2,500

Symptoms: temperature display blank or erratic, blower runs full speed only, no heat or A/C response, constant clicking from dash, system defaults to defrost

Fix: The electronic climate control module (ECC) and programmer assembly fail due to age. Programmer rebuild kits exist but require vacuum system diagnosis too—2-3 hours. Many owners convert to manual controls from donor vehicles.

Estimated cost: $400-850

Symptoms: intermittent gauge failures, power accessories working randomly, battery drain overnight, no crank no start intermittently, dome lights staying on

Fix: Corroded bulkhead connectors and failing BCM cause bizarre electrical issues. Diagnosis is time-consuming (2-4 hours) because problems are intermittent. Often requires connector cleaning, dielectric grease, and BCM replacement from salvage.

Estimated cost: $300-900

Typical onset: 70,000-120,000 mi

Symptoms: clunking over bumps, steering wander, uneven tire wear on inside edges, car pulls to one side, excessive body roll in turns

Fix: Control arm bushings, sway bar links, and strut rod bushings rot out. Not dangerous immediately but handling degrades significantly. Full front end refresh with alignment—4-6 hours labor.

Estimated cost: $600-1,200