What causes a automobile to throw a rode

Hi Lowco, there are really only two specific reasons a engine will "throw a rod." The first being oil pressure low enough to cause a rod bearing to spin out of its bearing cap on the crankshaft due to friction from lack of lubrication. When this happens, the rod detaches from the crankshaft and, depending on whether it occurs on the upstroke or downstroke, either smashes the liberated piston into the cylinder head or knocks a hole in the engine block. The other reason for low oil pressure is, well, no oil in the crankcase. The second reason being, over-revving. Over-revving an engine beyond its engineered limits can cause the rod, bearing or wrist pin to fail from excessive stress and heat. I hope this helps!

It doesn't really matter why- now you have a bad car with a bad engine- sell it for parts and move on-