I'm a little surprised to see crud like this on the tensioner pulley and the one above it. The belt doesn't look noticeably bad. Is this typical, or do you think it's from the very small antifreeze leak I'm trying to hunt down? I.e. Coolant getting lightly splattered around the engine compartment and turning into sticky crud when it lands somewhere hot like this? Is there anything I can/should do to keep this from happening?

 

I just changed my tensioner and belt over Christmas, had around 105,000 miles on it and didn't have any of that at all??