I have a 1994 Mercedes E320 station wagon. The other day I started the car and all the instrument lights were light up and not going away. Upon further inspection, I looked under the hood and notice the serpentine belt was not moving. In addition, the tensioner pulley was nowhere to be found. I walked around the area and saw the tensioner pulley on the ground. It appears worn out and I ordered a new replacement tensioner pulley. However, I checked the hole in the engine where the tensioner pulley goes in to make sure if it is clear and threads inside are o.k. The Tensioner pulley bolt or allen bolt is missing. I don't know the size, the type of thread, how long the bolt is. Is it a 10mm allen bolt? I researched the internet for this particular Belt Tensioner Pulley bolt or allen bolt and so far, no luck. Any helpful advice and show me where to get this particular bolt or allen bolt is greatly appreciated.