I completely ripped the threads out of one of those cooling water connections on a 220SEb head a few years back. (It was necessary to remove the fitting regardless of the consequences!) The local machine shop here in San Diego who specializes in Mercedes and other foreign products had no trouble repairing the hole by welding and rethreading it. So, do not get crazy with these fittings unless the head is off and you are willing to pay the price for thread repair. However, repair is possible if the shop is competent.