First Steps (Always):
* Safety First: Disconnect the battery's negative terminal to prevent electrical shorts and accidental starting.
* Identify the Problem: Before doing anything, try to determine *why* the engine is locked. This is crucial. Is it seized, hydrolocked, or something else? Signs might include:
* Seized Engine: Complete resistance to rotation, often accompanied by unusual noises during previous operation.
* Hydrolocked Engine: Resistance to rotation often linked to recent water ingestion (e.g., driving through a flood).
* Frozen Engine: Resistance to rotation due to extreme cold.
Possible Causes and Solutions:
* Seized Engine (Most Common): This usually means internal parts are stuck due to lack of lubrication, excessive wear, or a catastrophic failure.
* Penetrating Oil: Apply a good quality penetrating oil (like PB Blaster or Liquid Wrench) to all accessible engine bolt threads and the crankshaft pulley. Let it soak for several hours or even overnight, reapplying as needed. Try gently turning the engine by hand (using a wrench on the crankshaft pulley).
* Heat: Gentle heating can help the oil penetrate. Be extremely careful not to overheat any components. A heat gun on a low setting, focused on specific areas, is a potential option (but use caution). Never apply direct flame.
* Professional Help: If gentle methods fail, a seized engine likely requires professional attention. It may need complete overhaul or replacement.
* Hydrolocked Engine: Water in the cylinders prevents the piston from moving.
* Drain the Cylinders: Remove the spark plugs. Turn the engine over (carefully) by hand to expel the water. This may require considerable effort.
* Compressed Air: (Use with extreme caution!) You might use compressed air carefully to blow out water from the cylinders. Excessive pressure can damage the engine.
* Professional Help: If water is deep-seated and stubbornly lodged, professional help is recommended.
* Frozen Engine: This is most likely in extremely cold climates.
* Thawing: Allow the engine to thaw naturally in a warm environment (a garage, for example). Do not use extreme heat.
* Engine Block Heater (if applicable): Use an engine block heater if your vehicle is equipped with one.
Things to Avoid:
* Using excessive force: Forcing a locked engine can cause irreparable damage.
* Using a breaker bar or impact wrench directly on the crankshaft pulley: This can easily strip the pulley or damage the crankshaft.
* Ignoring the underlying problem: Fixing the immediate lock-up without diagnosing the root cause is a recipe for recurrence.
When to Call a Professional:
If you're not comfortable working on your engine, or if the above methods don't work, call a qualified mechanic. Attempting to force a locked engine can lead to expensive repairs or complete engine failure. It's always better to be safe than sorry.
