1983 BUICK LESABRE

Typical onset: 80,000-140,000 mi

Symptoms: Slipping between gears, especially 2nd-3rd shift, Delayed engagement when shifting from park to drive, Burnt transmission fluid smell, dark or metallic fluid, Complete loss of forward gears or reverse

Fix: TH200-4R overdrive and TH200C 3-speed transmissions both suffer from weak pump assemblies and inadequate lubrication to clutch packs. Rebuild requires 8-12 hours labor, includes new clutches, bands, seals, and torque converter. Preventive fluid/filter changes every 30k miles help but don't guarantee longevity.

Estimated cost: $1,800-2,800

Typical onset: 60,000-100,000 mi

Symptoms: White smoke from exhaust indicating coolant intrusion, Coolant mysteriously disappearing with no external leaks, Hard starting when warm, runs rough, Head gasket failure leading to cracked heads or block

Fix: GM's 5.7L diesel used weak head bolts and inadequate head gasket design, leading to notorious failures. Heads crack between valves, block cracks are common. Most require complete engine replacement or rebuild with ARP studs, upgraded gaskets, and machined heads. Figure 18-24 hours labor for engine removal, rebuild/replacement, reinstall.

Estimated cost: $3,500-5,500

Symptoms: Rough idle, stalling at stop lights, Black smoke from exhaust, fuel smell, Hesitation on acceleration, poor fuel economy, Check engine light due to mixture control solenoid faults

Fix: Computer-controlled Rochester carburetors on 231 V6 and 305/350 gas V8s have troublesome mixture control solenoids, rubber diaphragms that deteriorate, and clogged passages. Rebuild kits available but many techs swap to Edelbrock or Holley conversion. Rebuild takes 3-4 hours, conversion slightly more.

Estimated cost: $450-900

Typical onset: 100,000+ mi or age-related

Symptoms: Transmission fluid spots under vehicle near radiator, Low transmission fluid level causing slipping, Pink milkshake in coolant if internal radiator leak develops, Visible rust holes or weeping on steel cooler lines

Fix: Steel transmission cooler lines rust through from road salt exposure, especially where they attach to radiator. Requires line replacement (2-3 hours) and complete transmission fluid flush. If coolant mixed with ATF, transmission rebuild becomes necessary.

Estimated cost: $250-450

Typical onset: 70,000-120,000 mi

Symptoms: Excessive engine vibration at idle, Clunking when shifting from park to drive, Engine visibly sagging on one side, Fan contacting shroud or radiator

Fix: Rubber engine mounts collapse from age and heat, diesel's extra weight and vibration accelerates wear. Both front mounts typically need replacement together. 2-3 hours labor with engine support required.

Estimated cost: $300-500

Symptoms: Fuel gauge reads empty or erratic when tank has fuel, Hard starting after sitting, especially carbureted models, Stumbling under load from restricted fuel filter, Fuel pump noise or low pressure

Fix: Ethanol fuel damages rubber components and sender units from this era. Fuel sending unit replacement requires dropping tank (2-3 hours). In-tank pump (if diesel) or mechanical pump (gas) may also need attention. Fuel filter changes every 15k miles prevent carburetor clogging.

Estimated cost: $250-600