my friend has a 1995 dodge caravan with a 2.5 it has a knocking sound when u start it up cold . it sounds like it coming from the top part of the plastic timing cover .u opened the valve cover oil cap and the noise did not let louder , the noise goes away after it warms up maybe 5 mins or so. i have not taken this apart yet . i do know its time for the belt to be changed since it has 100,000 miles on it and its never been done . but he does not have a lot of money and does not want to put a belt on an engine that might be going south .. has anyone heard of the tensioner going bad for the timing belt i see they sell them as a kit i found that odd so maybe its a known problem ?

Yes, tensioner pulleys do go bad over time and this could be your issue. With 100,000 miles, its a good time to change the belt and tensioner pulley, too. The original belt in my 2.5 Liter Shadow went 103,000 miles before it let go at 65 mph on the freeway, 60 miles from home. Fortunately the 2.5 is a non-interference engine, so it was good to go with a new belt.