Hi perels,
Thank you for your reply and for providing an update on the status. I apologize for the delay in responding to your request.
You can use 3-In-One or sewing machine oil for the fan bearings if they are not sealed. Refer the picture provided below:
You may replace themwith aftermarket fans, if the lubrication fails to reduce the noise or if the bearings are sealed.
Please let me know about your findings.