Can you fertilize your lawn with used motor oil?

No...there is no 'nutrition' in used motor oil. It's petroleum. Fertilizers work by adding nitrogen and other nutrients to the soil. Besides, why on earth would you want to spread that on your lawn? Doing so causes it to leach into the ground, the water supply, and will probably kill whatever you might have growing.

Petroleum is toxic to plants, so keep it far away from any growing things. Used motor oil also picks up heavy metals from the engine, especially old engines, so it's even worse.