Alright, so a little back story first. Performed a boost leak test due to having a rich idle under load. I found multiple leaks during this test. Lower injector insulators, egr block off plate gasket, and T/B shaft seals. All of those have been replaced now, also in this process I added a Tial QR recirc. Pressure tested once again, found some small vacuum caps that need to be replaced and did so.

Fast forward to today, started noticing once again a richer afr. So, of course I boost leak tested to make sure I didn't miss anything else. When doing this, I started to hear a bubbling coming from inside the motor. Attempted to see if I was hearing things, and I wasn't. Popped open the oil cap and air pressure was indeed coming from inside there.

As it stands I've never seen this happen before, however I haven't performed many blt's before either. I tried searching, but didn't really come up with any answers. Most were speculations and done said it was normal. I asked mechanic friends if they've heard of this before, but they haven't.

Can anyone shed some light? Normal, or nah?

Also, I saw a few threads that suggested the pcv being bad, but mine is non existant as it is now a -10 an fitting to an open vent catch can.

Any help is much appreciated, thanks in advance.

 

It's air going by the seal rings in the turbo. The air then goes down the oil return line, and bubbles up through oil. It's normal.

 

Thank you for easing my mind!