How to Disassemble and Assemble an Engine?
3 Answers
Remove the cylinder head fixing screws, lift off the cylinder head, and take out the cylinder gasket. Loosen the oil drain screw of the oil pan and drain the engine oil from the oil pan. Remove the oil pan fixing screws, and take off the oil pan and oil pan gasket. Loosen the fixing screws of the oil coarse filter, and remove the oil filter, oil pump sprocket, and oil pump. Remove the piston connecting rod assemblies of the 4 cylinders, catch and take out the piston connecting rod assemblies at the cylinder outlet by hand, paying attention to the installation direction of the pistons.
A few days ago, I helped a friend disassemble an engine, and the steps are actually quite clear. First, I would disconnect the negative terminal of the battery to cut off the power, then drain all the fluids like coolant and engine oil. Next, remove the air filter box and intake pipe, and loosen the ignition coil and fuel injector wiring. The most challenging part is removing the exhaust pipe and transmission drive shaft, which requires special tools to support the flywheel. Before hoisting the engine, remember to remove the engine mount bracket bolts and use a support stand to stabilize the car body. The most crucial part of the entire process is marking everything clearly, such as which screw corresponds to which hole, and organizing small parts in compartmentalized boxes. When reassembling, always use new gaskets and manually pump oil to lubricate the internals before adding fresh engine oil. The whole process takes at least two full days, and if you lack experience, it's safer to have an experienced mechanic lend a hand.
Disassembling an engine requires extra caution. I once suffered significant losses due to impatience. Now, I prioritize preparing protective gear: safety goggles to prevent splashes and thick gloves to avoid cuts. In terms of tools, besides the standard socket wrenches, a ratchet wrench is particularly useful for tight spaces, and a torque wrench is essential during reassembly. During the operation, start by removing peripheral components: the alternator belt, air conditioning compressor bracket, and radiator hoses. When handling wiring harnesses, take photos to record connector positions, and use colored tapes for clearer differentiation. After the engine is lifted out, it's crucial to check the cylinder block for any fine cracks. Before attempting to start the engine post-reassembly, use a diagnostic scanner to check for fault codes, and repeatedly inspect the coolant level and oil pan seal under cold conditions.
