I've replaced the serpentine belt, tensioner rod, and damper shock on my '89 300 SEL, trying to find a way to quiet the whining from the belt when I start the car. When I turn the tensioner adjusting nut as far right as possible, the belt is still not taught (new belt), and it still whines when I start the engine. It seems to me that if I can't go any further clockwise on the adjustment, there's something I'm missing here. What is it that I don't understand about the way this works?

 

did you know that the adjustment bolt is a right handed thread? (opposite from normal).

you need to loosen the pulley a little before adjusting it.

be careful not to overtight... it get loose thread easily.

 

have u sorted ur problem. I too am facing this problem with the whinning. change the belt twice but still it comes back after 100 miles on the clock,. totally baffled by it