Actually I had it cleaned about three weeks ago. I have thought about the possibility of recoring it, but I am going to flush it first. I plan on doing so on Wednesday. If that does not fix the problem I will take it to the shop to see if a recore is possible. If not, I will replace it myself. I have located a radiator for a fair price, and Mike sent me very useful instructions for installation.
1976 300D (W115) - 330K and still going (sort of)
1991 300D 2.5 Turbo - Sold at 221K
1983 280SEL - Sold at 206K
1981 300SD - Sold at 232K