not to be pessimistic, but that knocking noise appeared on my friend's 300CD while driving along the highway. it was VERY loud and coming from the front of the engine. I told him to drive slowly and not to over rev it. He managed to make it about 10 minutes more, but of couse the idiot he is, didn't listen to me and was going
uphill doing at least 65mph.
You can see the results below, hope you had better luck than he did.
