1981 BUICK LESABRE

Typical onset: 60,000-100,000 mi

Symptoms: white smoke from exhaust, coolant mixing with oil (milkshake appearance), hard starting when warm, sudden loss of power, catastrophic head gasket failure

Fix: The Oldsmobile 350 diesel used inadequate head bolts and gasket design, leading to head gasket failures that contaminate the oil system. Typical repair requires engine rebuild with aftermarket upgraded head studs, new injector pump, and full gasket set. Expect 25-35 labor hours for complete rebuild. Many owners opt for gas engine swaps instead.

Estimated cost: $3,500-6,500

Typical onset: 80,000-130,000 mi

Symptoms: slipping in 3rd or 4th gear, no overdrive engagement, delayed engagement when cold, burnt transmission fluid smell, shuddering on acceleration

Fix: The early THM200-4R overdrive automatic was notoriously weak, especially behind the V8 engines. The overdrive unit fails first, followed by clutch pack burnout. Rebuild requires upgraded clutches, better torque converter, and hardened sun shell. Figure 12-16 hours labor plus parts, or consider a built unit from a specialist.

Estimated cost: $1,800-3,200

Symptoms: transmission fluid leaking near radiator, pink fluid drips under front of car, low transmission fluid level, transmission overheating

Fix: Steel cooler lines rust through at the radiator connections and along the frame rail, especially in salt-belt cars. Replacement requires new steel or upgrade to braided stainless lines. If leak allows coolant into transmission, flush and fluid change mandatory. 2-3 hours labor for line replacement only.

Estimated cost: $250-500

Typical onset: 50,000-90,000 mi

Symptoms: rough idle, hesitation on acceleration, black smoke from exhaust, poor fuel economy, stalling when cold

Fix: The dual-barrel Varajet carburetor on the 231 V6 develops vacuum leaks, stuck choke pull-offs, and clogged passages. Rebuild kits available but many techs recommend replacement with remanufactured unit due to warped throttle bodies. 3-4 hours for rebuild, 2 hours for replacement.

Estimated cost: $300-650

Typical onset: 90,000-150,000 mi

Symptoms: oil dripping from bell housing, oil puddle centered under engine, oil-soaked flywheel, transmission fluid contamination in severe cases

Fix: Two-piece rope-style rear main seals eventually leak, worsened by crankshaft wear grooves. Repair requires transmission removal, flywheel off, and seal replacement with modern lip-type upgrade when possible. 8-10 hours labor on RWD platform.

Estimated cost: $600-1,100

Symptoms: squeaking over bumps, doors misaligning, visible gaps between body and frame, floor vibration, cracked body mounts visible under car

Fix: Rubber body mounts deteriorate from age and oil contamination, causing body-to-frame contact and alignment issues. Requires lifting body slightly to replace each mount. All 8-12 mounts should be done together. 6-8 hours labor depending on rust severity.

Estimated cost: $500-900

Symptoms: brake fluid puddle on firewall, spongy brake pedal, low brake fluid warning light, gradual pedal fade

Fix: Plastic reservoir cracks at the mounting points or develops leaks at the seal to the cast iron body. Replacement with complete master cylinder assembly recommended over reservoir-only replacement. 2-3 hours including bleeding. Critical safety item.

Estimated cost: $200-400