Sounds like you are routing it wrong, have the wrong pulley on the water pump, or you're not pulling the tensioner far around. It takes a 2 foot breaker bar to lean mine over to put the spec belt on. You can't do it with a wrench. Should have about 4" of range.

 

ya it does and other pulleys do too.

 

ive used a long ratchet it comes across bout 4" or so like u say. its routed right. ive done it 5 or 6 times can almost do it in my sleep. theyre givin me a belt for no ac n i think the no ac has a smaller idler pulley thn w ac or a smaller pulley somwhere else. same pulley that was on old water pump, size that is.