throw a rod When you “throw a rod,” it means that one of these rods has literally broken off.

The motion of that piston is what makes the crankshaft turn–and ultimately what makes the car move. The metal part that connects the piston to the crankshaft is called a “connecting rod.” RAY: When you “throw a rod,” it means that one of these rods has literally broken off. When that happens, one of two things occurs.