Flywheels Garage is a business in Grand Theft Auto V.
There is a junkyard behind the building that seems to be shared with the airfield operation.
A random broken down vehicle will usually spawn in front of the workshop and there may be a mechanic working under it. Other mechanic NPCs may be standing in front of the door (usually using a Mobile Phone) or at the northeast corner of the building, sometimes smoking.
In the original release, the mechanics will be wearing coveralls with their names and JR Autos monogrammed on them. In the Enhanced Version, they will usually be wearing random outfits including various vehicle-branded shirts.
The mechanics will all respond aggressively if the player attempts to steal any vehicle from the forecourt. The two Globe Oil pumps on the forecourt are active and highly flammable.
Names of mechanics that can be found here