What does it mean when the engine block does not have a serial number stamped on it? This is regarding a 617.951 that appears to be a replacement motor on a '82 300SD because it has a couple of later model year parts on it.

The engine does not have the "Original Mercedes-Benz Tauschaggregat" tag found here in this thread for rebuilt motors. mystery 617: "Original Mercedes-Benz Tauschaggregat" = Replacement motor?

And where the serial number usually is (located behind the oil filter housing, on a flat surface on the block just below the head), the area looks like a factory casting with no evidence of it being ground off.

So am I looking at a possible "New" factory replacement motor? The other thing to note is upon looking down into the oil fill cap, the cam still has the machined ribs on the lobes given the car has over 300,000 miles on the odometer.


Any opinions?


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1983 123.133 California
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