Could be a terminology issue. I don't mean the plastic shrouds around the injectors. I don't think those are heat shields but I don't know what they are. When they break in the US, the dealer doesn't replace them. I mean the heat shields between the prechamber and the firing tip of the injector.

These things -

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1UF05A51E1XC0VPIWH&year=1993&make=MB&model=300-SD-003&category=All&part=Injector+Heat+Shield

Sixto
93 300SD