On my way to work this morning, my '87 300D started making a terrible noise. At first I didn't notice it, but then I accelerated rather hard, it made the noise, then I started listening very carefully. The noise only seems to get loud when the turbo really kicks in. It sounds like something is grinding. If the car is running under normal acceleration, the sound is almost unheard. I did discover that the noise got louder when I turned on the AC. I don't know if this was due to a heavier load on the engine. I doubt if it is the turbo as it was replaced not even a year ago. The noise appears to be coming from the very front of the engine. I removed the oil cap and took a peek in there with a flashlight and didn't see anything obvious. The car is running fine, no rough idling, plenty of power, etc. I am alarmed at the racket it is making though. Any ideas as to what this noise could be would be appreciated.

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Mike

'80 300D
'84 300D
'85 300D
'87 300D