Originally posted by acurars
im talking about the oil return line
A turbo's drain line depends on gravity to function properly. The oil from the turbo usually runs down to a fitting toward the top of the oil pan. If you routed the turbo's drain oil all the way to the back of the oil pan to the drain bolt, it would be below the oil level in the pan. If you did that, oil would stay stuck in the drain line, at a height equal to the level of the oil in the pan, and might even back-up into the turbo's CHRA. This will prevent the turbo from draining properly, which could cause the oil seals to fail prematurely. The drain fitting that you put in the pan needs to be as high as possible, in order to keep it above the oil level in the pan.