I have a 90 SC that still is in pretty good condition, with only 110,000 original miles. I was flushing out the cooling system and came to realize the stock oil cooler coolant lines are completely plugged. I dug out a bunch of rust and debris on the inlet side of the cooler and tried flushing/back flushing with water pressure to no avail. Does anyone have any ideas or experience with unclogging one? I know they are no longer available, and would like to get this system operable. If I can't unplug it, does anyone know where I can obtain one in good condition? Thanks for any help.