Your steamer should get up to around 212 degrees Fahrenheit. This will take care of nearly any bacteria present in your vehicle without damaging any surfaces within your vehicle. 212 degrees Fahrenheit is also the accepted temperature at which steam is produced, meaning nearly any steamer will be able to reach this temperature. It is likely that your steamer does not need to be any hotter than this in order to clean your vehicle effectively. Higher temperatures may even prove to be dangerous. In fact, while tackling pests such as bed bugs, excessive hot steam can prove to be ineffective.