[SierraStormZL1]

Newer ZL1 owner here. I tried looking around to find out what this hole is, but didn't find anything.

I recently took the car out for a spin and noticed that from a dig, it put out a fairly substantial plume of blue smoke behind me on more than one occasion. I hadn't noticed that ever happening before so this evening I pulled the MM catch can to see if it was full or something. It wasn't, barely had anything in it. Not even a drip. Granted I put it on less than 1k miles ago.

I then pulled the SC lid off and noticed that there was a hole in the front top passenger side of the Supercharger that was filled with oil. I hadn't noticed when I put the lid on earlier this year. The rubber pieces that go over the end there appeared to be lightly coated as well.

What is that hole for? Is that normal to have oil in it?

The car has not been tuned (next year) but I put on the RF CAI, DSX Lid, MM Catch can and Borla exhaust on it earlier this year and I don't recall it doing it prior to now.

No oil on the garage floor or anything. Did do a oil change a few months back and while the stick measures full, maybe it's a little too full and causing some sort of blow by?

[ZLRob]

The factory tune on these are pretty pig rich assuming the tune on yours is stock still. That, coupled with low friction lightweight piston rings that the LT4's already have from the factory and it allows for those clouds of smoke you are getting from take off.

My supercharger gets some oil in it as well after several thousand miles as well. I don't use a catch can like you do, but blowby on these is a fairly common thing. Unfortunately it's the nature of a high horsepower boosted application. I have made it a thing to remove the lid every few oil changes in order to give it a little wipe down in there to make sure I don't get excessive oil pooling up in there.

[SierraStormZL1]

Originally Posted by ZLRob

The factory tune on these are pretty pig rich assuming the tune on yours is stock still. That, coupled with low friction lightweight piston rings that the LT4's already have from the factory and it allows for those clouds of smoke you are getting from take off.

My supercharger gets some oil in it as well after several thousand miles as well. I don't use a catch can like you do, but blowby on these is a fairly common thing. Unfortunately it's the nature of a high horsepower boosted application. I have made it a thing to remove the lid every few oil changes in order to give it a little wipe down in there to make sure I don't get excessive oil pooling up in there.

Thanks for the response ZLRob. Yeah I'm still stock tune till next year. Any idea about the hole referenced in the pic? Is oil supposed to be there? What's it from or lead to? I haven't been able find any info about it.

[ZLRob]

Originally Posted by SierraStormZL1

Thanks for the response ZLRob. Yeah I'm still stock tune till next year. Any idea about the hole referenced in the pic? Is oil supposed to be there? What's it from or lead to? I haven't been able find any info about it.

Did you pull a bolt out of there by chance? There is A LOT of airflow moving in there so it shouldn't surprise me if oil just happened to puddle up in there due to that very fact.

[SierraStormZL1]

Originally Posted by ZLRob

Did you pull a bolt out of there by chance? There is A LOT of airflow moving in there so it shouldn't surprise me if oil just happened to puddle up in there due to that very fact.

No, no bolt removed. I finally found an image I could zoom in on.

Appears to be a drilled out area for perhaps that very reason, to capture oil that makes it to the outer edge? There is another one just like it on the opposite corner that also had some oil in it...closest to driver position. The lid has flat spots that cover these two areas. Dabbed it out, closed it back up.

[ZLRob]

Don't worry about it. I get oil in those holes all the time.

You're chasing nothing.