Originally Posted by John

oil isn't used for cooling, it's used to lubricate. If the oil returns through the valve cover, it will go down into the oil pan, same as the oil that is shot out to lubricate the valve train. Water is used to cool turbo center sections.

to the OP, yes, but remember the turbo oil return is best when gravity fed downwards, so every attempt should be made to have the oil return have a straight path downward. Any restrictions in the oil return line can cause increased pressure on the oil feed, which in turn can blow out seals in the turbo and the result is the burning of oil pushing past those seals. Typically, it's best you return it to the oil pan, which is easily modified to accept an oil return in most cases.