The question is in the subject line.... Actually there is another option too: local VW shop sells VW accessory oil pan heaters that are paper thin and glued to the bottom of the pan (after thorough cleaning, of course) with a special paste. Cost for this is about the same as the block heater.
No one locally seems to sell the circulating pump (plumbs into the lower rad hose) anymore, I keep getting told to go see an equipment or truck dealer. DieselGiant.com sells them customized, already plumbed into the correct lower hose for your Mercedes, for about $85. I have one OM616 and one OM617 to deal with. Thx Mac Aylmer, Quebec '60 220s / '82 240d (x2) / '82 300sd
