03 Malibu cranks but won't start ( don't think its a passlock problem)

You blow the engine when you over heated it.

You can change the spark plugs until the cows come home, but if you don't have tow things, spark at the plugs or fuel running through the injectors, you will not get ignition. That is what needs to be checked. Don't throw money into what doesn't need fixing until you get it running and then find what should be changed out. Make sure you have spark at the plugs first. Then see if you have fuel flow to the injectors. It could be a computer problem, sensors are sending messages to the engine not to start the engine. Have the codes read if you can. That may save a ton of problems. You even may have a wire to a sensor lose or off.

Engine coolant temp sensor is important..if it thinks the car is still overheated it won't allow you to start the car...unplug it and try to start it