Filter Queen and Royal motor noise question

[toastermike]

I have a Filter Queen Limited Edition with a 7.5 amp motor and a Royal 4600 tank with an 11 amp motor, both in excellent condition. When turned on, initially they are quiet like brand new. After they have run for a few minutes they begin to make a very slight soft growling sound. Is this normal after the motor gets warm or a symptom of a need for service, such as bearings?

 

[kirbyclassiciii]

toastermike

Mike,

I'd like to think it may be the bearings.

I remember that intermittent noise had come from both my Kirby Classic III and Dual Sanitronic 80 before I had them serviced.

Hope this helps you!

~Ben