* Lack of Oil: This is the most frequent cause. Low oil level, or using the wrong type/weight of oil, leads to insufficient lubrication, causing parts to overheat and seize. A blocked oil passage or a failing oil pump also contributes to this.
* Overheating: If the engine overheated severely, the metal components can expand and warp, leading to a seizure. This could be due to a faulty thermostat, radiator issues (leaks, clogs), a failing water pump, or a blown head gasket.
* Coolant Leak into the Engine Oil: A head gasket failure can allow coolant to mix with the oil, creating a sludge that restricts lubrication and damages engine bearings. This is often accompanied by milky oil or a loss of coolant.
* Rod Bearing Failure: These bearings support the connecting rods and crankshaft. Failure leads to metal-on-metal contact, resulting in a rapid seizure. This can be caused by lack of oil, low oil pressure, or excessive wear.
* Main Bearing Failure: Similar to rod bearing failure, but affecting the crankshaft's main bearings. This usually leads to a more catastrophic failure.
* Foreign Object in the Engine: While less common, a foreign object (like a piece of debris) could enter the engine and cause damage leading to a seizure.
* Extreme Engine Wear: Over time, normal wear and tear can eventually lead to excessive friction and seizure, particularly if the car hasn't been properly maintained.
To determine the exact cause, you'd need a mechanic to diagnose the problem. They'll likely need to inspect:
* Oil level and condition: Check for sludge, coolant contamination, or metallic particles.
* Coolant level and condition: Look for oil contamination.
* Engine compression: To assess the condition of the cylinders and rings.
* Visual inspection of engine components: To look for signs of damage or wear.
Without knowing the history of maintenance on your Buick and the circumstances surrounding the seizure (e.g., warning signs, recent repairs), it's impossible to pinpoint the exact reason. A professional mechanic will be able to provide a much more accurate diagnosis.
