I have been meaning to change my serpentine fan belt for some time, and already have the new one, BUT, I can't figure out how to release the tension on the old one to get it off, and put the new one on (and then put the tension back on for the new one). Little help please, as it is a tight squeeze in there between the radiator and fan and the belt, so I am having a hard time seeing what's what.

FYI - I just got a "friendly" reminder from the MB dealer with some coupons for summer service -- they want $150 to change the belt, and they "recommend" it be changed or checked every 30,000 miles. Cha-ching!