I was told to get a new tensioner when I needed to replace the water pump on the TE. Sure enough, the rubber was frayed, I'd have needed one if I hadn't gotten the new one.
With the new visco clutch, this was a $600 water pump....
Good news is that it works perfectly now.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!