Your car doesn't have a timing belt, MB diesels have chains. Your car is a W123 chassis which came in 3 bodies, 4 door "D", 2 door "CD" and wagon "TD". The "T" in "TD" stands for touring, as in when the family goes for a "tour" of the country, they take this type of vehicle. Starting in 1982 the cars had turbos on them.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member