I did a boost leak test last week sing the A4mods.com how to. Found a small leak and fixed it. But I also noticed an oil bubbling sound coming from the crankcase. This would indicate boost leaking into the crankcase and pressurizing it. To my knowledge, the most likely cause would be a check valve, correct? If not, any other idea's? 2 of them have been recently replaced with revised ones.

Now, I also have an oil consumption problem. I am adding oil every 2 weeks. Not a lot of oil but still having to add it. I can see oil on the drivers side of the block and under the oil filter area. I don't know if its leaking from the valve cover/tensioner gasket or if its leaking from where the dipstick goes into the block (it looks wet at the dip stick) This would sorta go hand in hand with the boost leaking into the crankcase.

The PCV valve in the TIP has been cleaned out, the PCV valve under the manifold is brand new and the car is thoroughly maintained since i've owned it. Any idea's/thoughts on this? I guess my next step is manually checking the check valves.

 

From what I've read in the past, the bubbling during the leak test is normal. Mine did so when I checked mine. If you're still loosing boost, you may have another leak.

 

I has a small leak at the intake temp sensor on the manifold. The O ring was shot so I replaced it. I still have the oil bubbling.