Happy Memorial day everybody!!
I need your expertise please, Has anybody every experience the knocking/smoke sounds from the video attached at 1:30 minutes? This isn’t my video, but my engine has a developed the same sound as in the video, well for the last month, ( I have gone through several tanks of fuel and from different station) When I change from “Park” to Drive or Reverse the knocking sound appears. And this is with the brake pedal pressed and in gear, I hear the same knocking sound as in this video. '92 300SD Engine knock and smoke - YouTube the smoke happens when the engine is cold and goes away when the engine warms up.

I am going to change the oil and try a few gallons of B99 to a ¼ level of my fuel tank , and if the sound disappears after adding the B99 I will defiantly know that it’s the injectors, but if the sound is still there it might be a lifter, even though they were replaced 28578 miles ago, or this might be an early sign the original head gasket may have started to fail and has started slowly contaminating to oil supply stream of the lifter, clogging them , and causing them to make a knocking sound as in the video. I am open to ideas if anybody has any suggestions J

Background information
1987 Mercedes 300D current of Mileage 158578
Original 14 cylinder head, never seen it over heat.
Chain stretched to 5 degrees ( hasn’t been changed yet, waiting for the head to crack so I can replace it with a #16)
Lifter replaced at 130,000 miles
Replaced nozzles in 12/01/2011 to Monark /pop test/balanced
Glow plugs have been removed and bench tested twice.
Changed Fuel Filters Twice since 12/01/2011
Change oil every 3000 miles with Rotella 15-40 and I use a Wix oil filter. Every oil change I drain the oil into a huge tray and run a magnet to find metal, I but haven’t found any metal in the oil, and drain the oil though a fine screen

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1987 300D