The video says 240D. But the lighted sunvisor mirror says 300D (unless those options are a-la-carte for W123s in Europe).
Wasn't impressed with the big screws holding the wood trim to the dash.

My solid-body 240D, with a factory replacement engine, is pretty quiet when revved or cruising on the highway and passing power is decent. When pushed, that engine sounds closer to a 4-cyl gasser. It's actually quieter than my '84 Euro 300TD. Then again, the Euro has more rust and perhaps less soundproofing and maybe the open cargo bay magnifies noise.
Either car is serene compared to my first diesel - a $200, rusty & tired automatic 240D, well thrashed by the PO's teenagers. That car was nearly deafening at speeds above 60 mph!

Happy Motoring, Mark

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DrDKW