1997 CADILLAC ELDORADO ETC

Typical onset: 80,000-150,000 mi

Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Overheating under load or at highway speeds, Oil in coolant reservoir or milky oil on dipstick, Misfires and rough idle as gaskets deteriorate

Fix: The aluminum block's head bolt threads strip out, allowing head gaskets to fail. Proper fix requires time-sert thread inserts in all 20 bolt holes per head or full engine removal for block replating. Budget 18-25 hours labor for heads-on repair with inserts, 35-45 hours for engine-out full rebuild with new gaskets, studs, and machine work. Many shops won't touch it, sending you to Northstar specialists.

Estimated cost: $3,500-7,500

Typical onset: 70,000-120,000 mi

Symptoms: Pink milkshake appearance in coolant overflow tank, Transmission slipping or delayed engagement after mixing fluids, Coolant in transmission pan during fluid change, Sudden transmission failure after overheating, Puddles of red fluid mixed with coolant under vehicle

Fix: The internal transmission cooler inside the radiator fails, allowing coolant and ATF to mix—destroys the 4T80-E transmission quickly. Requires radiator replacement, transmission flush minimum (2 hours), but if fluids mixed for any length of time, full transmission rebuild or replacement needed (12-16 hours). Many owners don't catch it until trans is cooked.

Estimated cost: $800-4,200

Typical onset: 60,000-100,000 mi

Symptoms: Severe clunk when shifting from Park to Drive or Reverse, Vibration through chassis at idle in gear, Transmission appears to shift hard or jerk, Visible engine movement when revving in Park

Fix: The hydraulic transmission mount deteriorates and collapses, allowing excessive drivetrain movement. Replacement requires supporting the engine/trans assembly and is tight work in the engine bay. 2-3 hours labor with proper equipment.

Estimated cost: $350-550

Typical onset: 90,000-140,000 mi

Symptoms: No-start condition with cranks but won't fire, Stalling while driving with no restart, Intermittent stalling when engine is hot, Check engine light with crank sensor code

Fix: Sensor behind the harmonic balancer fails from heat. Requires removing balancer and accessory drives to access. If you're in there, replace the balancer and front seal too as preventive. 3-4 hours labor.

Estimated cost: $450-700

Typical onset: 80,000-130,000 mi

Symptoms: Overheating despite full coolant level, No heat from heater core on cold days, Coolant circulation visible stops in overflow tank, Squealing from water pump area, Pieces of black plastic in coolant system

Fix: The plastic impeller breaks apart inside the housing, destroying coolant circulation. Often misdiagnosed as thermostat or head gasket until pump is removed. Requires coolant flush to remove debris after replacement. 4-5 hours labor, and if debris circulated long enough, can contribute to head gasket failure.

Estimated cost: $550-850

Typical onset: 70,000-110,000 mi

Symptoms: ABS light on constantly, Traction control light illuminated, Loss of ABS function in emergency braking, Traction control activates inappropriately or not at all, Speedometer works but codes present

Fix: Front wheel speed sensors corrode at the connector or sensor face on the bearing hub. Rear sensors less common. Sometimes just connector cleaning works, often needs sensor replacement. 1-1.5 hours per side.

Estimated cost: $200-400