I have a 6.2 with banks turbo, and there's oil leaking from the lift pump. I assume the cause is blow-by from the Turbo. The leaking stops when I remove the oil cap, and the blow by has an escape.

My question: is this common? Shouldn't the seals be able to support the blow by pressure? my oil pressure is normal according to the gauge, and I have 2 new gaskets in place over the cover and lift pump...

Maybe you need to clean/replace your CDR?

Hello Lee!

I thought I would just start a new thread with this problem, to keep things interesting ;-) I'll clean the CDR tomorrow and see if that works. It's lame that those seals leak so quickly though, because the blowby shouldn't put that much more pressure on the liftpump (or rear main seal)...

Well, it's good that it comes out around the pump plate, that releases the pressure ...

HAHA - Very Funny! I'm still burning oil though, blue smoke... I suppose it could be the rings. is it a good idea to use thicker oil to prevent leaking?

Seriously, I had oil leaking all over the underside of the oil pan on the Tahoe when the vacuum pump didn't work so that the wastegate remained open. I could hear a sound like something cracking or exploding a couple times but couldn't figure out what it was. The pressure must have blown out through the oil pan seal or so, making that noise. Once the wastegate and thus the turbo was working again, that didn't happen again. Since the CDR was connected to the inlet side of the turbo, there must have been insufficient vacuum on the CDR for it to work. I'm glad that nothing was damaged and that the seal didn't start leaking ...

What oil are you using? If you run anything thicker than 15W40 or SAE30, you might get problems while the oil hasn't reached operating temperature. And where does the oil come from, is it leaking from the turbo into the intake?