2000 Dodge Durango serpentine belt is too tight

Hello, i just replaced my serpentine belt and my tension pulley. My belt is way too tight and I don’t know how to loosen it. Any help would be great thank you

You can’t loosen it. If it is really too tight, you may have the wrong belt or you can try a different brand or you have the wrong tensioner, one more ‘or’ the tensioner is improperly installed-doubtful. I found on one vehicle one brand of belt was slightly larger and would slip.
But, how did you determine the belt is too tight?

My belt gets really really hot when I start it. What can that be ?

I would like others to comment. But to me heat would be generated from slipping. Is there a squealing noise when yo first start the engine? Do all pulleys appear to be rotating at the same speed? I realize that pulley speed would be just a guess.

Yes when you start it it’s a squeak

A very loud squeak

There must be a seized pulley, alternator, A/C compressor, idler pulley or water pump.

That would indicate either the belt is too loose or something is dragging or failing. You could remove the belt then turn each pulley by hand to determine if one is stiff. This would be subjective but might indicate a problem area.
This is where I need others to join in. I THINK everything should turn with little effort.
There might be a deflection test, ie pressing on the belt, x inches of deflection with x amount of force, I do not know. You might find a service manual at the library.
As mentioned earlier, I had the squealing on startup, got a different brand of belt and that resolved the issue.

So I took off my belt and moved all the pulley and all work good. Then I reput my belt back on the started it. The belt tightened and my car won’t start up now

Have you checked a belt routing diagram to make sure you have the belt routed correctly?

Yes I checked and it’s right