did you know a locked up a/c compressor clutch has enough power to keep the engine from starting. i figured that out with 2 new engines thinking they were defective.i finally replaced the clutch and it started right up.
That's odd.Once when I was working at Ford dealership,a Taurus came in with major belt squeal.One of the guys popped the hood and started it up.The AC clutch locked the pully up and the belt was burning up bad smoking and all.I guess if the belt and tensioner are both in top shape then it could prevent the engine from turning.