My car broke down last week, I'm so thankful for auto mechanics
I know what you mean, my best friend is a mechanic and does a variety of automobile makes but others work in specific areas.
Yeah my mechanic is a genius at mostly everything. What are some specific areas a mechanic my specialize in?
Well, for instance some only work on transmissions, etc.. of course their main role is to diagnose the problem accurately and quickly.
Okay I see. Luckily my issue was just a water hose and not a huge issue like a transmission!
Was it an item that may have been found during basic vehicle maintenance ?
I'm not too sure. I just noticed liquid leaking underneath and my car would overheat if I ran it too long. I was worried it was the radiator. 
So in your case it involved the repair of a specific part, but in some it can be the replacement of entire assemblies.
Yes I was glad it was only one part. But it still cost me more because of the placement of my hose. Most cars are above the engine, mine was below. More money spent on labor.
Because this means that parts are replaced before any problem is observed, many vehicle owners will not understand why the expense is necessary.
With the rapid advancement in technology, the mechanic's job has evolved from purely mechanical, to include electronic technology. Because vehicles today possess complex computer and electronic systems, mechanics need to have a broader base of knowledge than in the past.
Due to the increasingly labyrinthine nature of the technology that is now incorporated into automobiles, most automobile dealerships and independent workshops now provide sophisticated diagnostic computers
Auto mechanic
An auto mechanic (automotive technician in most of North America, light vehicle technician in British English, and motor mechanic in Australian English) is a mechanic with a variety of automobile makes or either in a specific area or in a specific make of automobile. In repairing cars, their main role is to diagnose the problem accurately and quickly. They often have to quote prices for their customers before commencing work or after partial disassembly for inspection. Their job may involve the repair of a specific part or the replacement