G35X Clicking won't start
 

I know there are a bunch of starting threads on the forum but don't quite see end answer to my problem. I thought my battery was bad and jumped it (with a lot of effort) had it checked and was told it wass ok little low needed some charge. I hadn't driven the car in around 2 weeks went to start it seemed like dead battery again. Bought a new battery still wouldn't start. It would just click. I tried to jump even the new battery and engine seems to slightly turn with revving the jump car but wouldn't start. From what I read on here, seemed like it would be the starter. Mechanic replaced it and checked everything still won't start. They are telling me the Engine is bad which I don't see much of common occurrence on here. Mechanic said engine is hard to turn. Could something be binding off the drive belt not letting it spin? Alternator AC compressor? I checked oil was fine no metal in it. I was worried coolant seemed low in overflow but was totally full when open radiator. Any insight would be much appreciated. I find it hard to believe engine is bad with 90k miles on it. Thanks for the help.

Disconnect the drive belts, pull all the spark plugs, put it in neutral and turn the motor by hand with a socket in the crank pulley nut. It's pretty obvious when you have a spun bearing because it turns REALLY hard.

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