auto factory vs car factory

auto factory and car factory both are nouns.

Word	Noun	Adjective	Verb	Adverb
auto factory	Yes	No	No	No
car factory	Yes	No	No	No

As nouns, auto factory and car factory are synonyms defined as:

auto factory and car factory: a factory where automobiles are manufactured

Other synonyms of auto factory include automobile factory.

auto factory (noun)	car factory (noun)
a factory where automobiles are manufactured	a factory where automobiles are manufactured