1987 CADILLAC FLEETWOOD

Typical onset: 60,000-100,000 mi

Symptoms: White smoke from exhaust indicating coolant burning, Rapid coolant loss with no visible leaks, Overheating despite new thermostat and water pump, Oil milkshake appearance from coolant contamination, Loss of compression in multiple cylinders

Fix: The aluminum HT-4100 block was cast with porosity issues causing coolant seepage into cylinders and catastrophic head gasket failures. Head gasket replacement alone (12-16 hours labor) rarely fixes it because the block deck surface warps. Most require complete engine replacement or rebuild with block sleeving. Expect 25-35 hours for engine R&R plus rebuild costs.

Estimated cost: $4,500-8,000

Typical onset: 70,000-120,000 mi

Symptoms: Pink milky transmission fluid indicating coolant intrusion, Transmission slipping or delayed engagement after cooler failure, Coolant reservoir showing oily residue, Sudden transmission failure after engine overheating event

Fix: The cooler lines running through the radiator develop pinhole leaks or the internal cooler fails, allowing coolant into transmission or vice versa. Once contaminated, the THM200-4R transmission requires complete flush, torque converter replacement, and all internal seals. Cooler line replacement is 2-3 hours, but contamination damage adds 8-12 hours for transmission service.

Estimated cost: $1,200-2,800

Typical onset: 80,000-140,000 mi

Symptoms: Loud ticking or tapping from valve covers at idle, Noise increases when cold, may quiet slightly when hot, Loss of power and rough idle, Check engine light with misfire codes if severe

Fix: The roller hydraulic lifters collapse from oil contamination (often coolant intrusion from head gasket issues) or simple wear. Lifter replacement requires intake manifold removal on this engine. All 16 lifters should be replaced together. Expect 8-10 hours labor plus lifter set.

Estimated cost: $1,200-1,800

Symptoms: Stalling at idle or when coming to stops, Surging or hunting idle between 400-800 RPM, Hesitation on acceleration, Service Engine Soon light with TPS or fuel system codes

Fix: The early digital fuel injection system uses a problematic TPS and DFI module prone to heat-related failures. TPS replacement is 0.5 hours, but diagnosing intermittent DFI module issues can take 2-3 hours. Module replacement/repair requires specialized knowledge of the obsolete system.

Estimated cost: $400-1,200

Typical onset: 90,000-150,000 mi

Symptoms: Clunking when shifting into drive or reverse, Vibration felt through floor at highway speeds, Visible transmission sag when inspected on lift, Exhaust contact noise from shifted transmission position

Fix: The rubber transmission mount deteriorates and allows excessive movement. This creates driveline angles that accelerate U-joint wear and can crack exhaust components. Replacement is straightforward at 1.5-2 hours but requires proper transmission support.

Estimated cost: $250-450

Typical onset: 80,000-120,000 mi

Symptoms: Rear end sagging overnight or after sitting, Compressor running constantly when car is on, Harsh ride from collapsed air shocks, Warning light on dash for suspension system

Fix: If equipped with automatic level control, the air compressor eventually fails or air lines crack at fittings. Most owners convert to conventional coil springs and shocks (3-4 hours labor) rather than repair the obsolete system. Compressor replacement alone is 2-3 hours but doesn't address aging lines and shocks.

Estimated cost: $600-1,400