How to Replace a Car Engine?

[McGrant]

When replacing a car engine, you should apply for a modification registration at the vehicle management office of the registration location. After replacement, the engine number must be reported to the vehicle management office. Go to the license and certificate management office to process the engine modification, undergo an inspection, and if the inspection is passed, the modification will be approved. It is not allowed to replace the engine privately. As the device that outputs power, the engine must be compatible with other parts of the car, such as the transmission system, cooling system, etc.

[OTravis]

Replacing a car engine is a major project that requires professional repair shop expertise. The first step involves dismantling peripheral components, disconnecting all hoses and wiring, and removing drivetrain connections. Before hoisting out the old engine with a crane, ensure all fluids are drained. Next, verify the compatibility of the new engine model and clean carbon deposits and sludge from the engine bay. During installation, align the mounting bracket screw holes and tighten each fixing bolt to the torque specifications in the repair manual. When reconnecting hoses and wiring, pay special attention to the foolproof design of harness connectors. Finally, refill with new engine oil and coolant, match the ECU programming for startup testing, and conduct a road test to check for transmission jerking and power response. The entire process takes approximately two days, and it's recommended to choose remanufactured or identical model engines to ensure compatibility.

[DiZoey]

I tried replacing it myself once, and the conclusion is: absolutely don't attempt it! First, you have to lift the car onto a lift, disconnect the battery, and drain all the engine oil and coolant. The engine is surrounded by a dense network of pipes, each needing to be marked to avoid reassembly mistakes. The transmission half-shaft connection was the hardest to remove—even an impact wrench struggled. It took three people to coordinate the hoisting; the slightest imbalance could damage the radiator. The new engine's bolt holes were off by half a millimeter, making it impossible to install, forcing a return. After reconnecting all the wiring plugs, the car threw error codes upon startup, requiring a $600 ECU reprogramming. The whole ordeal took two weeks, ended up costing $3,000 more than a repair shop, and left me with back pain for half a month.

[McJaxson]

The key to engine replacement lies in the disassembly sequence and attention to details. First remove the air intake pipe and exhaust manifold, then loosen the suspension bracket nuts. Avoid the firewall and subframe during engine hoisting. Thoroughly clean the new engine's mounting surface and tighten the fixing bolts in three diagonal passes to specified torque. Prioritize ECU connector when reconnecting wiring harnesses, ensuring proper contact for oxygen sensor and crankshaft position sensor. Manually prime oil pump to build oil pressure before initial ignition to prevent dry friction damage. Throttle position calibration is crucial to avoid unstable idle. Remember to replace all rubber seals to prevent oil leaks.