I am not sure I would be able to stomach straight garlic oil. I think you could mix some garlic oil in with another oil to get benefits, or perhaps chop garlic and let it sit in another oil for a while then strain it out and use the infused oil?
You will also get good garlic results just from eating it, and then good antibacterial results from oil pulling, so you can separate the garlic part from the oil part and not miss out on anything if you don't OP with garlic oil.