Simple question. On a 1981 318 904 which line going to the radiator is the inlet and which is the outlet? I want to do a complete fluid change on my car more than you get when you drop the filter. So planning on running like a dialysis setup with two old gallon milk jugs one for old fluid and one for new ATF+4. It would be nice to know which is which beforehand. NOT a power flush but natural fluid exchange through line pressure.
