BlackSE

I have a 2006 IX with the stock turbo on it and I believe I have a boost leak in my turbo because the car does not feel as quick as it did before. I've done a lot of searching and this is what I have come up with. I have done several boost leak tests, doing it the proper way of plugging the turbo inlet with a cap and valve, capping my MBC and valve cover breather and pressurizing the system. There are no boost leaks in my inter-cooler piping, I replaced throttle body shaft seals about 8 months ago and at the same time I shaved down the spacers for the fuel injectors so they would hold better. Also I have checked my PVC valve and it is holding fine. They symptoms I have now are:
-Boost is slowly leaking out of the system. Using my boost gauge I can see that it drops at a steady rate of about 1 psi every 2 seconds.
-Boost coming out of the oil cap when doing a test. The cap holds most of the boost but when I open it all of the pressure drops.
-My boost gauge needle jumps around a lot when I hit higher rpms (6k and up) in 3rd and 4th gear. It will start jumping from 17-23 psi and I have it set at 21 psi, which is what it reads at lower rpm. My car has an AMS base flash for now and a Hallman MBC.

These symptoms along with the fact that I have some turbo shaft play lead me to believe that boost is leaking through my turbo. The shaft play isn't a lot side to side and there is none in and out. The side to side play is not causing the compressor to touch the housing. I know when the car is on there is oil pressure that helps hold boost but not while doing a boost leak test and the car is off. So I suspect that boost is leaking through the turbo oil lines and escaping through the open valve cover breather that is connected to my intake. Is there anything I can further do to confirm my suspicion before possibly rebuilding or replacing the turbo? I have thought of running thicker oil but it seems like 10w-30 Mobile 1 is what everyone uses and I've been using it for a while now. Any information would be helpful because I would like to fix this problem before getting a tune. Thanks.

BlackSE

anyone shed some light

zeus1

iTrader: (19)

seems like you have done your due diligence, why not bring it to AMS, explain your situation and have them help confirm your theory of a bad turbo?

BlackSE

I probably will take it to a shop just to double check, I just wanted to get some input from some people on here first.

dastallion951

well more then likely if your leakin boost through the turbo are you leakin oil or coolant, you can always disconnect the downpipe, and see if you have either of those leakin out the hotside? iirc, the best way to tell with shaft play, dont you measure the play with a dial indicator on the middle of the compressor blades, and move it to see how much play it has?

BlackSE

That's a good idea, I'll measure how much shaft play I have and post it. I was also thinking, would it be possible that my crankcase is being pressurized through the piston ring seals? I haven't done a compression test. though I think I might have to.