shown in this video is a squealing noise of 1KD engine of Toyota Prado. the 3 pulleys have been replaced. drive belt is new. harmonic balancer is not slipping. the squealing noise comes on and off. i think drive belt tensioner spring has become weak causing the drive belt to slip and squeal. someone has diagnosed and replaced the 3 pulleys and belt but did not fixed the problem.
please listen to it and comment below if you agree with my diagnostic. thank you.
note: engine fan was removed to mount the GoPro cam in the radiator.