Noisy left fan on old MacBook Pro

Yes.

MacBook Pros have been made in dozens of variants since their introduction is 2006 so we need to have more detail about your specific model. All fans are ultimately replaceable but some may requre a professional technician to access.

First find your computer's serial number. This article will help:

How to find the serial number of your MacBook Pro - Apple Support

Please enter your computer's serial number in this Apple Support Page:

https://checkcoverage.apple.com/

It should return a full model description like this:

Telling us the full model name will help us help you. Please DO NOT post your actual serial number here, however.