auto-mechanic vs automobile mechanic

auto-mechanic and automobile mechanic both are nouns.

Word	Noun	Adjective	Verb	Adverb
auto-mechanic	Yes	No	No	No
automobile mechanic	Yes	No	No	No

As nouns, auto-mechanic and automobile mechanic are synonyms defined as:

auto-mechanic and automobile mechanic: someone whose occupation is repairing and maintaining automobiles

Other synonyms of auto-mechanic include car-mechanic, grease monkey, mechanic.

auto-mechanic (noun)	automobile mechanic (noun)
someone whose occupation is repairing and maintaining automobiles	someone whose occupation is repairing and maintaining automobiles