1982 CADILLAC ELDORADO

Typical onset: 60,000-90,000 mi

Symptoms: coolant consumption with no visible leaks, white smoke from exhaust, overheating, loss of compression, oil contamination in coolant

Fix: HT-4100 suffers from aluminum block porosity and head gasket failures that lead to coolant intrusion. Typical fix requires long block replacement or complete engine rebuild. 18-24 labor hours for R&R plus machine work. Many owners swap to Chevy 350 instead of rebuilding the original engine.

Estimated cost: $3,500-6,500

Typical onset: 50,000-80,000 mi

Symptoms: hard starting when warm, excessive blow-by, sudden loss of power, knocking sounds, fuel in crankcase oil

Fix: GM's 350 diesel has inadequate head bolt torque, weak crankshaft, and poor injector pump design. Head gasket failure leads to coolant in cylinders and hydrolock. Most need complete short block replacement including crankshaft and main bearings. 20-26 hours labor. Parts scarce and expensive.

Estimated cost: $4,500-7,000

Typical onset: 80,000-120,000 mi

Symptoms: slipping between gears especially 2nd-3rd, delayed engagement when cold, no overdrive function, burnt transmission fluid smell, shuddering on light throttle

Fix: The THM325-4L overdrive transmission has weak intermediate band servo and governor issues. Transmission cooler lines frequently corrode causing fluid loss. Full rebuild includes band replacement, clutch packs, seals, and torque converter. 12-16 hours labor. Replace cooler lines and external filter during rebuild.

Estimated cost: $2,200-3,800

Symptoms: intermittent no-start, stalling when warm, rough idle, check engine light codes 12 and 51, poor fuel economy

Fix: Early electronic fuel injection module (ECM) on 4.1L and 368 V8 fails due to capacitor deterioration and heat damage. Module is under hood and gets heat-soaked. Requires ECM replacement or send out for rebuild. 2-3 hours diagnostic and replacement. NOS parts expensive, rebuilt units available but quality varies.

Estimated cost: $800-1,500

Typical onset: 70,000-110,000 mi

Symptoms: oil puddles under rear of engine, oil coating on transmission bellhousing, low oil level between changes, oil drips on exhaust causing smoke

Fix: All three engines develop rear main seal leaks due to crankshaft wear and hardened seals. Requires transmission removal for proper access. While trans is out, replace pan gasket, valve covers, and front seal. 10-14 hours labor depending on engine. Diesel version more complex due to injection pump clearances.

Estimated cost: $1,200-2,200

Typical onset: 60,000-100,000 mi

Symptoms: clunking over bumps, steering wander, tire wear on inside edges, shimmy at highway speeds, loose steering feel

Fix: Front control arm bushings, strut rod bushings, and sway bar links all wear prematurely on this heavy FWD platform. All rubber components should be replaced together for proper alignment. 6-8 hours labor plus alignment. Original Cadillac parts no longer available, use quality aftermarket.

Estimated cost: $900-1,400

Symptoms: AC blows hot air, heat doesn't work, blower stuck on one speed, temperature display incorrect, mode doors don't change position

Fix: Electronic climate control programmer under dash fails due to vacuum solenoid failures and circuit board issues. Diagnostic requires vacuum pump and pressure gauge testing. Programmer replacement or rebuild required. 3-4 hours labor. Rebuilt units available from specialty shops.

Estimated cost: $600-1,100