Heat creep is caused when heat is radiated upward from the heat block. It would be nice if the Creality build instructions would include removing the two screws from the heat block supporting the radiator as they caused my large prints to be destroyed because there was too much heat into the guide tube which caused early melting of the filiment. The results were a buildup of deformed filament above the nozzle. Then the tube is pushed up with hot filament under pressure. Remove the 2 screws and do a PTFE mod and large prints are working now.