Serp belt tension
 

I don't have a belt tension gauge. Is there a poor man's way of knowing the belt is adjusted right?

When installed you should be able to grab the belt with to fingers and with a little effort twist the belt from a flat position to straight up and down basically 90 degrees. Check at longest span between pulleys. Serpentine belts really don't need to be that tight. When you have one that uses a spring tensioner you can pull the belt off by hand no tools if that helps give you an idea of tension...

Thanks! I'll give that a try.

I replaced my water pump impellor last week and can usually get it back on without loosening the tensioner. This time I figured I'd make my life easier by loosening it. After running it, I thought the belt looked like it was vibrating a little more than usual.