2005 yukon 5.3 bored and sts turbo about 10psi. have always had problems with oil. It used to push oil dipstick out (atleast that is where it was belived to leak form) which is fixed with a springs holding it down. now it leaks where the oil return is attched to the oil fill cap and tube. I put a new tube and o-ring and i thank atleast for now it fixed at the bottem of the tube. at the top of the tube where the cap screws on still leaks unless you put pressure down on it somehow? any ideas or somewhere else that you could tap into easily.

 

Read through this it should give you some help.
I fixed most of my isses but still have slight oil leakage.
Make sure you have a check valve type PCV valve. Otherwise you can be venting boost into your crakcase.
https://www.performancetrucks.net/fo...d.php?t=363972
Did this too.
https://www.performancetrucks.net/fo...d.php?t=363258