Oil in intake / filter

[DCoy3]

Hi this is my first post here, purchased my z/28 last fall. Was cleaning out the air filter getting it ready to bring out of hibernation and noticed oil on the bottom side of my filter, the housing below it and inside the intake tube. Is this normal for these ls7 engines? Should I consider a catch can? 9,600 miles bone stock. Thanks!

[1970judge]

More than likely someone oiled the shit out of the filter. Which is NOT necessary, nor recommended.

[DCoy3]

Originally Posted by 1970judge

More than likely someone oiled the shit out of the filter. Which is NOT necessary, nor recommended.

I thought that at first too but the fact that it's only on the bottom side of the filter and that it's on the inside of the intake pipe makes me think it's coming from maybe the pcv. I searched some zo6 forums with the ls7 and sounds like it's a common problem with the pcv tieing into the dry sump. Oil can burp into the pcv especially if slightly over filled and end up in the intake box.

[ariZona28]

Originally Posted by DCoy3

I thought that at first too but the fact that it's only on the bottom side of the filter and that it's on the inside of the intake pipe makes me think it's coming from maybe the pcv. I searched some zo6 forums with the ls7 and sounds like it's a common problem with the pcv tieing into the dry sump. Oil can burp into the pcv especially if slightly over filled and end up in the intake box.

I'd say get a new filter and give the intake a good cleaning. Drive it for a while and see if the oil returns. The Z/28 and early Z06 oil tanks are different so I wouldn't use that as a reference.

[69L48Z27]

I like the ‘someone oiled the filter’ theory. Would that much oil flow against the air coming in? That would be a pretty violent burp to push it out the filter.

[DCoy3]

I cleaned the box and replaced the filter. Will check back after I drive it for a bit. Thanks for the comments!

[joelster]

Over oiled the filter, and over time the oil seeped into the bottom of the filter and finally dripped down. Some of it was sucked into the intake tube as well. You're supposed to gently spray the oil to the outside of the filter element when applying it.

[ariZona28]

Originally Posted by joelster

Over oiled the filter, and over time the oil seeped into the bottom of the filter and finally dripped down. Some of it was sucked into the intake tube as well. You're supposed to gently spray the oil to the outside of the filter element when applying it.

I thought the ORIGINAL air filter is a dry unit and does not get oiled like an aftermarket K&N?

[69L48Z27]

I think oiled filters and LS’s with MAF sensor is bad news. Oil gets in the MAF and ruins it. I did a GMPP LS3 crate engine and the paperwork said absolutely no oiled filters.

[pzero]

My two cents worth. Modern cars don’t need oiled filters. Too many computer gizmo so it will mess up the sensors. Clean it out real good and dry, get a new air filter, clean / spray MAF sensor and you should be good to go. FYI take out the MAF not while it’s inside. Follow cleaner info. Congrats on your Z/28, it’s a beast of a machine. Not the fastest, but one hell of old school raw machine.