You might think about getting a 'whirlybird' vent put up high in the garage, even if you can only install it at ceiling level if there's living space above it (there are types that can be 'angled-up'). My garage used to get up to 110F if I had the doors closed, I put one of those vents in the roof and now it rarely gets about 85F (typical summer outdoor temp in the shade). I got the whirylbird put in when the roof was replaced, single-story house. Just an idea if you own the house you live in.
