Thanks all for the advice... I took it up to the semi-local MB dealer here first so I have a paper trail if the first MB dealer botched it in some expensive manner. 4 hr round trip with traffic, grr...
If that fails I'll go the multiple degreasing route myself and see what happens. That degreaser that gpracer posted looks especially effective:
Do you have to tranquilize 'em first before you run them through the radiator?
I'll report back in a week... in the meantime I'm a proud driver of a (shudder) Kia.
