Now this is really annoying! M104 Belt Tensioner
 

I bought a belt tensioner awhile ago and decided to put it in when I had a few other things to do.

I car has been driving fine. I've had the belt off a few times, but did it by loosening one of the pulleys rather than thru the belt tensioner. One unnerving thing was the white plastic indicator on the tensioner was off the ramp way to the left. After studying these essential posts, I realized this was not a good thing. While replacing the smog pump, I noticed quite a few cracks to the belt, one all the way across all the ribs right where the belt is joined, so I thought might as well do the tensioner now. In the photo, the one on the left is the one I removed. On a good tensioner, the line from the center of the pulley should be parallel to the two flat spots . You can see on the old one, the two flats pointing off to the right. There was a little spring action left but there was also a lot of grease around the front of the tensioner. I take this to be the grease from the bearings inside the tensioner being squished out. These essential threads show how to test your old or new tensioner. Before installing I tried to test my new one. With a crescent wrench on the two flats I could spin the tensioner both ways, but no tensioning action and no return back to the resting central position! I take this brand new tensioner to be DOA. Am I correct?

How annoying! I bought it awhile ago, and I hope the company is still around to get a refund.

glenmore
1991 300CE
2000 C280
1990 LS400



http://www.peachparts.com/shopforum/tech-help/156146-removing-power-steering-pulley-belt-tensioner-replacement-87-300e-103-124-a.html?highlight=300e+belt+tensioner+replacement


http://www.peachparts.com/shopforum/tech-help/129793-drive-belt-tensioner-failure-analysis.html

http://www.peachparts.com/shopforum/tech-help/129491-drive-belt-tensioner.html