* Head Gasket Failure: This is a very common cause of overheating and fluid expulsion. A blown head gasket allows combustion gases to enter the cooling system, pressurizing it. When the engine cools down, the pressure is released, forcing coolant out. This often results in white smoke from the exhaust and sometimes milky oil (from coolant mixing with oil).
* Cracked Cylinder Head or Engine Block: Similar to a head gasket failure, cracks allow coolant to mix with combustion gases or to simply leak out under pressure. This is usually a more serious and expensive repair.
* Radiator Cap Issues: A faulty radiator cap can't maintain proper system pressure, leading to overheating and coolant loss. It might not be sealing properly or the pressure valve might be malfunctioning.
* Water Pump Failure: A malfunctioning water pump won't circulate coolant effectively, causing overheating. You might hear unusual noises from the pump if it's failing.
* Thermostat Issues: A stuck closed thermostat prevents coolant from circulating properly, leading to overheating. A stuck open thermostat will mean the engine takes longer to reach operating temperature but shouldn't cause overheating, though it might slightly lower efficiency.
* Cooling Fan Issues: If the cooling fan isn't working correctly (either the fan motor itself, the fan clutch, or the electrical controls), the engine might overheat, especially at idle or low speeds.
* Blocked Radiator or Heater Core: Restrictions in the coolant flow path (due to debris, corrosion, or internal damage) will hinder cooling.
* Blocked Radiator Fins: Dirt and debris can clog the radiator fins, reducing their ability to dissipate heat.
Diagnosis:
Determining the exact cause requires a proper diagnosis. Here's what you should do:
1. Pressure Test the Cooling System: This is crucial. A mechanic can pressurize the cooling system to check for leaks and identify the source of pressure.
2. Inspect the Radiator and Hoses: Look for any visible cracks, leaks, or kinks in the hoses and radiator.
3. Check the Water Pump: Inspect for leaks or listen for unusual noises.
4. Check the Thermostat: Ensure it opens and closes properly.
5. Inspect the Cooling Fan: Confirm it operates when it should (often triggered by temperature sensors or a separate fan switch).
6. Check for Exhaust Gases in Coolant: Look for signs of combustion gases in the coolant (white milky substance in the coolant reservoir or oil).
Because multiple components can cause these symptoms, it's best to take your Cadillac to a qualified mechanic for diagnosis and repair. Attempting fixes without proper knowledge could worsen the problem and lead to significant engine damage.
