For only models listed below from 1980 to 1991. Check color of your plug before ordering.
New Plastic Drain Plug. Fits all models listed below:
Late 123 and 126 Chassis Blue Plastic Radiator Drain Plug
$6.95
SKU:
DSL/GEG-COMRDP 
Product Details
Mercedes-Benz 240D
Mercedes-Benz 280CE
Mercedes-Benz 280E
Mercedes-Benz 300CD
Mercedes-Benz 300D
Mercedes-Benz 300SD
Mercedes-Benz 300SDL
Mercedes-Benz 300TD
Mercedes-Benz 350SD
Mercedes-Benz 350SDL
Mercedes-Benz 380SE
Mercedes-Benz 380SEC
Mercedes-Benz 380SEL
Mercedes-Benz 420SEL
Mercedes-Benz 500SEC
Mercedes-Benz 500SEL
Mercedes-Benz 560SEC
Mercedes-Benz 560SEL