A female who is obsessed with cars can be referred to as a "car enthusiast" or simply a "car lover." The term "gearhead" is also commonly used to describe someone, regardless of gender, who has a strong passion for automobiles and everything related to them. It's worth noting that gender-specific labels like "car girl" or "car chick" have been used in the past, but they may be considered somewhat outdated or gender stereotyping. In modern times, it's best to use inclusive and gender-neutral terms when describing people's interests and passions.