A visible mechanical part (or multiple parts) of a car, such as an engine or its part, a turbocharger, a brake disc, transmission etc, excluding wheels and fasteners (bolts, screws and nuts). The parts may be either removed from a car, or be installed on it, but be visible enough to properly identify, such as under the open hood, or exposed by design (such as in post #5877255).
Vehicle body parts (bumpers, fenders etc) count too, as long as they are removed from the vehicle at least partially.
Not to be confused with the similar tag mechanical_parts, which should be used for androids, mechas and other robot-like characters.
Related Twitter tags: #ใใๅบใใฎใจใณใธใณใ่ฆใใฆใใฃใจ
TBD: create a broader tag vehicle_part, which would include tanks, rail vehicles, etc.