OKAY! Thanks for everyone's replies to my original question. I've got a lot of good stuff to work with.
NOW, another part of the question...
When the tensioner unit "wears out", which part is it that keeps the tension on and actually needs replacing?!?!?!?
I've got a Performance Parts catalog for my wife's 190E 2.3 and the exploded diagram shows a "belt tensioner shock". Is this the part that wears out and fails to keep the tension on the serpetine belt? If so, is this the part that needs replacing (at a cost of $35 instead of $172) rather than the whole unit?
What advantage is there to replacing the entire assembly instead of only the shock?
I hope that these are "good questions" and that many people will benefit from the answers. Thanks in advance!!
1989 300 E
1992 190-E 2.3