: While primarily a paid game, it frequently hosts "free weekends" on Steam. It allows you to build vehicles from scratch using bearings, engines, and sensors.
: Many sites promising "free full versions" of paid software contain malware or "cracks" that can compromise your PC. car-constructor-pc-game-free-download-full-version
If your interest is more about the "engineering" and seeing if your creation actually drives (or crashes), these sandbox games are excellent: : While primarily a paid game, it frequently
The base game is an older cult classic, but there is a massive community around "MWM" (Most Wanted Mod) versions and total conversions that are often shared in enthusiast circles. It features some of the most granular "part-by-part" engine building ever seen in a game. Physics-Based Sandbox Builders : While primarily a paid game