Just bought a 2006 Explorer XLT. Many miles. After a hard freeze w/ no antifreeze, engine overheated and the then owner stopped and had vehicle towed home. Mechanics don't want to tackle the job. New engine to costly. I decided to use BlueDevil and try to seal leaks. Got all the preparation done and went to crank it so I could pour the radiator flush in to start the process and it wouldn't crank. I UTubed it and checked fuses, etc. Had starter rebuilt and installed it. Nothing! Mechanic friend said it sounded like a power problem so I cleaned post and tighten everything up. Charged the battery and still no start. Starter bumps hard, but no crank. Any ideas?