I am Having the same Issue with my steering belt. My Mechanic says the one thing you can't do is get a "cheap" belt. This after I spent the $20.00 on some cheap Kragen belt... now he tells me ...as I go in every 40-50 days to have it tightened.

I will have mine replaced with his reccomendation, in a week or two, just was waiting for the 110k service to come up.