Strange noise from the engine of a BMW E46?
You can listen to it in the link. I suspect it's due to a connecting rod bearing failure. However, I drove it for over 2,000 km without noticing any changes. When accelerating, the noise gets faster and a bit louder, but when the engine warms up, the noise doesn't change either. https://youtube.com/shorts/Wm6jHNodnO4?feature=share
I can’t tell you exactly what this is, but at least it doesn’t sound like a connecting rod bearing damage.
In step 1, I would remove the V-belt and then try again if the sound is still there. But don’t run long because the cooling water pump may no longer work.
Have you checked the oil level?
Sounds like untiring connecting rod bearing damage, which if it is not eliminated destroys the crankshaft and that is—depending on how old the car is—a total damage equals. In any case, an exchange motor becomes susceptible.