CDH76

I was bored so I decided to take off my intake tube and look at things. I noticed there is two lines running to it. One is coming from the valve cover area and the other runs to the dry slump oil reservoir. Can someone explain to me what is going on here with these lines? I'm guessing this is the built in "catch can" that GM designed for the Z51?

The part in the intake tub (where line runs from it to oil reservoir) had some oil in it. I turned it upside down and probably less then a 1/4 cup of oil came out.

Just trying to get educated on this. I think I might understand what is going on here but figured I'd ask.

Thanks

Higgs Boson

there is no built in catch can.

the valve cover lines run FROM the intake ports to the valve covers to supply fresh air to the crankcase for the pcv system as the intake pulls vacuum on the crankcase. under excessive RPMs/crank pressure/high lateral Gs oil could reverse out the fresh air lines into the intake tube. I haven't really seen this on the C7 yet but it happened a lot on C5s and C6s.

The other line on the Z51 is a burp/pressure relief line for the dry sump system and if your oil is overfilled it can pump oil into the intake tube as you experienced.

CDH76

Ok. So I got my oil changed at 500. I'm now nearing 4k miles. So I guess it didn't over full too much, correct? Assuming this and th fact I emptied it out I shouldn't have more oil in there before my next change?

Thanks Higgs!

Higgs Boson

I would hope you're good to go but every dealer is different.