It should work although Diesels tend to not run as hot so it might be smaller than you need. A 450SEL radiator should have sufficient capacity. This has been for sale forever if you're in the area -
https://sfbay.craigslist.org/eby/pts/d/radiator-450-sel-mercedes/6350866485.html
Not mine, no stake in sale. At least check the pictures to see if a 450SEL radiator can be made to fit your car.
The top and bottom tanks of your radiator are metal so maybe a local shop can fabricate a core at reasonable cost.
Sixto
98 E320s sedan and wagon