Search the Library catalog for "automobile mechanics" on catalog and you will get some results. Be sure to write down the call numbers of any books you find and look at books near these numbers when you get to the stacks. Also, try to think of other search terms that might be used such as "repair" or "cars" when doing keyword searches.
Also, the library subscribes to an online database called the "Automotive Repair Reference Center" which may contain useful data for you. Go to the Library homepage and choose "Research by Subject"; chose "All Databases A-Z" and find it in near the top of the list in the "A" listings.