Left fan of 2006 MacBook Pro sounds weird

Apple does not have parts for that MacBook Pro, which it considers obsolete. Any service options would need a third-party provider to obtain and install used parts salvaged from a dead MacBook Pro of the same model-year.

Given that MacBook Pro can only run AT BEST MacOS 10.7.5, its capabilities are severely limited, and it likely can not even get on the Internet.

Any money you spend would be FAR better applied toward a Mac that can at least run MacOS 10.11 El Capitan, and an Apple-silicon Mac of ANY description would be vastly superior.

Computers are a commodity. Every MacBook Pro of that same model-year has the same capabilities, and they have no ART or Collectible value worth talking about. It's time to let that obsolete computer go.

Your big issue is that the 2006 pre-Unibody models are not easy to open for accessing and inspection. Yours is too old for Apple to touch, and some computer techs in private practice were still in diapers when the model was the newest thing.

You can see if a loose bit of metal or plastic is making the noise by lifting the computer and holding it at different angles while it is running. Does the sound change with that movement? If so, a loose bit of something is in a fan.

If the sound does NOT change with movement, that could be a noisey hard drive. It is also on the left side in that model.

Hi, ok. Please log out and turn off your computer. Ensure that it and anything connected to it has been unplugged from the electrical outlet.

If you feel comfortable working on your mac, you will use the instructions to open the casing.

use a DRY paper towel or clean dust-free cloth to clean any dust off. The fan is easily reachable. Inspect it and remove the debris that is causing the sound.

It could be a screw or nut that has become loose or you might need a new fan which is fairly easy to replace. It is as easy as swapping out one for another.

Please do not use your computer with the fan making sounds. I hope this is helpful.

There are instructions on Apple’s YouTube channel.

FWIW, I would not spend any money getting an obsolete/vintage computer "looked at" or repaired.

I would be looking at new computer buying options.