I had my '80 300SD up on a friends lift to install a block heater. The car did not originally have one. ( I don't know why) That pipe plug was one tough mother. We broke a couple of 1/2" drive components before using a standard "L" shaped allen wrench (3/4" I believe) and about a 4 foot pipe. Both me and my buddy were applying as much force as we could on that plug before it finally broke loose.

The flip side is that it sure is nice having a working block heater.

SteveM.

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner