1. Visual Inspection:
* Check for obvious damage: Look for any signs of external damage that might indicate a seized engine, such as bent or broken parts, leaks, or significant wear and tear.
* Inspect the oil: Check the oil level and condition. A low oil level or milky, frothy oil can indicate problems that *could* lead to a seized engine (lack of lubrication). However, the oil itself won't directly tell you if the engine is *currently* seized.
* Look for leaks: Leaks around the engine can also point to underlying problems that might have contributed to a seizure.
2. Physical Tests (These require some mechanical knowledge and caution):
* Attempt to rotate the engine: This is the most crucial test. Use a wrench on the crankshaft pulley (or a suitable socket on a nut on the crankshaft itself if accessible) to try and turn the engine by hand. Important safety note: Ensure the vehicle is in park (or neutral if possible and safe) and the parking brake is engaged.
* Free turning: If the engine rotates smoothly with relatively little resistance, it's not seized.
* Stiffness or resistance: If there's significant resistance or the engine won't turn at all, this strongly suggests a seized engine. Don't force it! Forcing it can cause further damage.
* Intermittent resistance: This could indicate other problems (like a broken connecting rod) and warrants further investigation by a mechanic.
* Check the compression: (Requires a compression tester) Low or zero compression in one or more cylinders is a strong indicator of a problem which *could* be a seizure. However, low compression can also be caused by other issues (e.g., a blown head gasket, valve problems).
Important Considerations:
* Don't force it: Attempting to turn a seized engine with excessive force can cause irreparable damage.
* Safety first: Always disconnect the battery before working on the engine.
* Professional assessment: If you're unsure or uncomfortable performing these checks, take your vehicle to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately.
What causes an engine seizure?
Engine seizures are typically caused by a lack of lubrication, leading to excessive friction and heat, which causes the metal parts to weld themselves together. Common causes include:
* Low oil level: The most common cause.
* Oil pump failure: Prevents oil from circulating.
* Blocked oil passages: Prevents oil from reaching critical components.
* Overheating: Excessive heat can break down the oil, leading to seizure.
In summary, while a visual inspection can offer clues, the definitive test for a seized engine is the inability to rotate the crankshaft by hand. If you suspect a seized engine, seek professional help to avoid further damage.
