Confirm the replacement’s thread, length, diameter and temperature rating before heating the printer. A nozzle that merely looks similar may not seal against the heatbreak.
Unload filament. Follow the nozzle-replacement section of Creality’s V3 SE manual, including the specified hot temperature and tools. Hold the heater block in the documented position so torque does not twist the heatbreak or wiring. Wear heat-resistant protection and keep hands away from the block.
Tighten by Creality’s method, reinstall the silicone sock and inspect every wire. Update the nozzle diameter in the slicer, run leveling and print a small first layer.
Stop if plastic appears above the heater block or temperature fluctuates. A leak at the hotend joint needs correct reassembly, not more flow or retraction.
Picking the right replacement is easier with background: our nozzle size guide explains what changes beyond the stock 0.4 mm option, and the brass vs hardened steel comparison helps decide which material suits your filament. Once the new nozzle is installed, folding this check into the regular maintenance schedule keeps it from being forgotten again.