Okay, that can't be good...

[etoven]

Try to put some oil in it, there should be a small hole in the center of the fan just under the label. If that doesn't work...well, there's probably not a whole lot you can do about it.

I wouldn't put anything wet and conductive (including oil) anywhere near dripping range of your main board or GPU. GPU fans are designed to be oiled at the factory and then carefully dried. My suggestion is to just pick up a new GPU fan for about $20 bucks, you can find them on many web sites and are extremely easy to install.

Absolutely don't let an old fan run on your graphics card:

1. They can be load and annoying
   
2. They can case your GPU and or graphics card to overhead and die.
   
3. The problem could cause cooling issues to many devices connected to the graphics card, including your main board, CPU, and RAM.