there is a little gear which can get out from it place in time. Check its position and if its moved - use a glue to hold it at place. here is an example of wrong position of the gear: If you can't figure out where is the gear in a printer - look at the bottom right corner of the picture: If you need a replacement part: (1) google tne next text "pinion gear 10T 0.3M bore 1.5mm"; (2) also spare parts for RC helicopters can be applied, for example MH-BP031015
How much is a temperature should be?