Turbo Brass Fitting

I've got alot of oil pouring through the brass fitting that attached to the oil return line top of the turbo. Tried 2 days ago to put some thread sealer on it but didnt seem to hold and picked up a new fitting from a local auto store but the female was to big. Size is what 1/4" to 1/4"?

Either the brass fitting or the oil supply line may be damaged/cracked. You need to determine which and replace the appropriate part.