How to Free a Seized Engineby John Stevens J.D.
Engines rarely seize, but when they do, it is almost always due to a long period of nonoperation. When an engine seizes, one or more pistons have literally become stuck against the cylinder's wall. Thankfully, just because an engine has seized does not necessarily mean that the entire engine must be rebuilt. The keys to freeing the engine are to reduce the air pressure within the engine's cylinders and to reduce the amount of force necessary to break the piston free by disconnecting the components that the engine turns, such as the alternator and power steering pump.
Remove all of the engine's spark plugs with a socket wrench to alleviate the air pressure within the engine's cylinders. First, pull each spark plug's wire off the tip of the spark plug. Attach an appropriate-sized spark plug socket to a socket wrench; then remove each spark plug by turning the wrench in a counterclockwise direction.
Remove the accessory belts from the alternator, power steering pump, and any other belt-driven accessory. Each accessory attaches to the front of the engine with one or more brackets. The brackets are in turn attached to the engine with retaining bolts. Loosen the retaining bolts on each accessory bracket with a wrench; then slide the accessory toward the engine to reduce the tension on the accessory's belt. Slide the loose belt off the engine to remove it.
Remove the valve covers from both cylinder heads by removing each valve cover's retaining bolts located on the lip of each valve cover with a wrench; then pull the valve covers off the cylinder heads to access the rocker arms.
Remove the rocker arms and pushrods to remove the amount of force necessary to turn the engine. Each rocker arm is held in place with a single nut located in the center of the rocker arm. Remove the nut for each rocker arm with a wrench, then pull the rocker arms off the cylinder heads. Removing the rocker arms will free the pushrods, which can simply be pulled out of the cylinder head.
Turn the crankshaft to free the seized engine. Since the engine's pistons are attached to the crankshaft, turning the crankshaft will free the pistons. The engine's crankshaft can be turned with the single bolt located in the center of the circular harmonic balancer, which is located on the bottom of the front of the engine. Attach the appropriate-sized deep socket to this single bolt; then apply steady force to the socket with a socket wrench. The bolt should be turned in a clockwise direction to avoid inadvertently loosening the crankshaft's bolt before the crankshaft turns.