My daughter drove my car through a big puddle. The car died 3/4 of the way through and would not start again. Had the starter tested and it is good.

Your car went in the water and died. for some reason you tested the starter. was that because it will not crank and will not start? Take the spark plugs out and turn the engine by hand. Does water come out the holes? It could have ate water. yes that's the industry term for water went in the intake through the fresh air intake into the aircleaner and the engine, running at the time sucked it in an hydrostatically locked. This could mean it bent something, like an engine crankshaft to piston CONNECTING ROD, that's what we do not want to hear, but it's possible. You would have trouble changing one unless you had the top end off and the pan off in chassis. It is also possible there are more than one at fault. Your GM dealer can diag it for internal damage. Once you have the water pushed out, the starter back in, crank the engine with the plugs out. if it acts out of balance, you may be all done. if not, put the dried plugs back in and start it. see if it is noisy or shaky, make sure before starting that the oil is not half water by a high reading or water coming out when you loosen the pan plug, report findings and think about all the water logged places that need cleaned and dried. flushed etc. see what evidence you have, or take it to the shop now.