Just put on my KB turbo kit a couple weeks ago on my 2007 Sierra 5.3. I am running out of ideas on what to change to stop the blue smoking. I don't have any problems with it at start up. It really only happens idling after I've been in boost (doesn't happen all the time). I have the turbo clocked straight up and down. The oil return is the shortest that I can get it. I have the oil return into the pan above the oil low level sensor and a couple inches back. I have both of my valve covers vented under the hood. What is the best place to start?

Do I need to vent my valve covers to pre turbo vacuum?
Is there something with my PCV that is causing this?
Is it bad for the turbo to leak oil past the seal?
As a last resort, do I need to restrict my oil feed line?
Where does the oil level actually sit in the oil pan during running conditions?

Thanks for the help!

 

I have mine setup the exact same way... Except I tapped my oil pan in the front, to the right of the crank. I would think it's either the turbo, or oil pressure? what does your oil pressure read at idle and when driving?

 

I was under the impression that you had to restrict the oil feed so you didn't blow oil past the seals on the turbo.

Maybe someone with more knowledge will chime in.

 

It depends on what turbo it is. Mine takes -4.

What turbo is this OP?

Do you have the tube coming off the TB to the passenger valve cover capped off?

 

For ball bearing turbos you're supposed to run a restrictor on the oil feed line, but with journal bearing you're not supposed to have to run any kind of restrictor.

OP, is this a 07 classic, or nnbs?

 

The turbo is a precision PT72/68. When I took both of the valve cover tubes off I capped the intake. Specifically the passenger valve cover vent to the throttle body and the port on the side that runs back to the driver side vent.

My oil pressure at idle is 40 to 45 psi if I remember correctly. I'll have to check when I leave work.

 

Its journal bearing. 07 Classic! I love it.... If it didn't smoke...

 

I think the pcv system is setup a little different on the classic vs the nnbs.... You can get a restrictor and put it in line, on your feed.... Would be the easiest place to start! But like I said they're not re commended for journal bearing..... But if you have blue smoke I would think there is definitely oil being pushed past the seals? If it was my truck that is where I would start

Plus your oil pressure goes up significantly when driving and boosting! So it makes sense that oil is getting past the seals and then it's smoking after a pull when idling.

 

Something like this? Do you know what size hole I would need?

 

That's exactly what you'll need! As for the size... I don't know? But what I would do is order two of them and compare them to the opening on the line you have right now, then if it's a lot smaller, I would open one up a little (with a small drill bit) and try it out... It's just gonna be a trial and error thing. I would imagine just a tad bit smaller then what you're running now would work great though! Because it's not pushing oil through at all times, only after hard driving.