Hi. I replaced my serpentine belt and tensioner and there was quite a loud whine coming fries it. All was good for about a month and now I have a huge knocking from the top front of the engine, and what appears to be near the starter area. The sound only comes on in low idle or low idle under load. Once rpms go past 1000 it stops. Different forums suggest it could be the starter nor disengaging fully and the gear is bouncing off the flywheel. Here is the video. Initially I thought the sound was near the back but once I crawled underneath it seems to be middle to front of van.

 

Sound like a/c compressor clutch bearing gone bad shut the a/c off to see if it makes less noise. One of my trucks years ago made a similar sound turned out to be bad a/c clutch bearing.

 

Good call. i am going to take the serpentine belt off and run the engine. Then I’ll narrow it down