it is a relative vacuum thing. The intake manifold has more vacuum than the pressure outside the TB, so the air flows from the TB to the valve cover. I suppose if your PCV valve on the drivers side valve cover was blocked, it might suck up toward the TB. But I think you would have all sorts of codes from that.
Oil catch can options
- Thread starter HACK BLOCK
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it is a relative vacuum thing. The intake manifold has more vacuum than the pressure outside the TB, so the air flows from the TB to the valve cover. I suppose if your PCV valve on the drivers side valve cover was blocked, it might suck up toward the TB. But I think you would have all sorts of codes from that.
I was thinking about this some more and along maybe with a plugged PCV valve, you might could also have enough ring blow by that you have essentially a pressurized crankcase that is putting out more volume than your PCV/Intake manifold can vacate, hence your "pressurized" fresh air side. That could cause vapors (oil) to be pushed up the fresh air hose and into the TB stream. But again, that would cause a bunch of codes, I would suspect.
HACK BLOCK
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so correct me if I'm wrong but the driver's side pcv vacuum goes from the valve cover to the manifold right? and on the passenger side vacuum goes from the intake tube into the engine?. I'll tell you what I know for sure is that the TB had oil all over it and also that breather tube on the passenger side had oil in it too. plus when I looked into the intake tube I can see oil residue
If you have oil in the tube that runs from your TB to the passenger side valve cover (the fresh air tube, there to provide filtered air to the crankcase), then the only two things I can think of is you either have a plugged PCV (on the drivers side) and/or you have so much blow-by that you have a pressurized crankcase, one less bad than the other.
There may be other explanations, but those two are all I can come up with.
Yes. At full throttle, there is going to be close to zero vacuum in the intake manifold. So at full throttle, the crank case vapors will flow out of both valve covers, and oil vapor will come out of both. This is normal. Now how much oil vapor may be a question of how much blow by. In any case, catch cans on both hoses will help.
trailblazer
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I’m not sure how that moisture laden emulsion gets there. Every time I’ve pulled my plastic intake off (5.3 and 4.8) I’ve seen a pool of the milky emulsion sitting in there.
HACK BLOCK
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do you think I would be able to tap both lines into one catch can or would it choke everything up?
iamdub
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I agree with this.
I agree with this, as well.
I’m not sure how that moisture laden emulsion gets there. Every time I’ve pulled my plastic intake off (5.3 and 4.8) I’ve seen a pool of the milky emulsion sitting in there.
This is why these engines need a catch can!
No. They need to be separate since they're separate directions of flow. But, I'd be more concerned as to why you have so much oil on that side of the intake and in that fresh air intake tube. Do you constantly drive it hard? As @wsteele mentioned, check you PCV system. Yours, being a 2011, should have the updated valve cover. But, running crappy oil or not changing it frequently enough (running dirty oil) could clog up small passages such as that small orifice in the valve cover that acts as the PCV "valve". I'd pull that driver's side cover off to (1) have a decent idea of the condition of the inside of your engine and (2) to clean the cover and PCV orifice thoroughly. I'd try to blow through it to see how difficult it is before and after cleaning to gauge if there was any improvement. Clean the TB and that fresh air inlet hose, too.
trailblazer
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Come to think about it, I haven’t inspected the induction system for the milky emulsion since I’ve installed the catch can system. I get a ton of emulsion in the catch can though.
HACK BLOCK
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I cleaned out the TB when I removed it and bought a new breather hose. I'll also try to take pictures of the intake tube where I see the oil residue just so everyone and see what I'm seeing.
Just Fishing
Can't fix stupid
the main thing to focus on is the primary side for a catch can.
the side that goes from the driver side valve cover, and then right into the top of the intake.
I just snipped the plastic line and attached the extension for my catch can.
The other side is not a priority.
This is how i choose to do mine.
Mostly i had aluminum line left over from my vette project, and not enough silicone hose.
Too lazy to go to the store, this is how i ran it!
the red ends are the flex joints.
the long red line at the bottom of the fuse box is the flex joint for the can side.
The bits of red hose in the middle serve as an isolator, purely there to keep the hard lines from rubbing together, and against other hard objects.
the silicone hose was also left over from my vette project.
It's color scheme is red and silver...
the side that goes from the driver side valve cover, and then right into the top of the intake.
I just snipped the plastic line and attached the extension for my catch can.
The other side is not a priority.
This is how i choose to do mine.
Mostly i had aluminum line left over from my vette project, and not enough silicone hose.
Too lazy to go to the store, this is how i ran it!
the red ends are the flex joints.
the long red line at the bottom of the fuse box is the flex joint for the can side.
The bits of red hose in the middle serve as an isolator, purely there to keep the hard lines from rubbing together, and against other hard objects.
the silicone hose was also left over from my vette project.
It's color scheme is red and silver...
Just Fishing
Can't fix stupid
careful cleaning out the throttle body, if you move that butterfly you mess with the IAC function.
The engine will idle funny/high until it relearns.
If you have a tech 2, you can do a quick relearn.
otherwise it's a few drive cycles.
iamdub
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Dont have anything to say that hasnt been said so heres a pic of my setup haha
View attachment 270025
@iamdub what can do you have ? It kinda looks like mine but I completely forgot what one mine is
Yours and mine are the catchcans.com one. I put a 1/4-turn valve ($5ish at Harbor Freight) in the bottom of mine to make draining easier and mess-free. I also added a stainless steel scrub pad to it to improve the can's efficiency. I saw recently that some of the cans on Amazon are coming with a scrub pad.
It's a $100+ can, but I bought it back around 2011 in a group purchase before they were so popular. IMO, the $15-$20 ones on Amazon work just as well, they just have less capacity and don't have the fancy mounting bracket. I just checked my build thread. Apparently, I loaded the pics of the scrub pad through Photobucket, so they're all dead links now.
Drok
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Ha, yeah that one. I bought this one probably close to that time frame also. Ill have to look up that 1/4 turn part and scrub pads. Thanks
HACK BLOCK
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ok so when attaching the lines to the pcv do I cut that hard line and attach a hoes to it or if I completely remove the line there will be a nipple to attach to?
HACK BLOCK
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the pics are mixed up but u can see the breather hose nipple with oil on it. I tried to take a couple of pictures of inside the breather tube, and I took a picture of inside the intake tube with some residue
iamdub
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It really doesn't matter. All you need is an airtight path between all the nipples, whether it be soft hose, hard line, copper or aluminum tubing, etc. Some cut the factory hard line and slip them inside the rubber hoses and some remove the factory line altogether and slip the rubber hoses over the nipples. There's a steel nipple on the rocker cover- that one's easy. The nipple on the intake manifold is plastic and, therefore, BRITTLE. Do NOT bend it in any direction or it'll snap like a pretzel stick. I used a razor knife to slice the factory hose and peel it off this nipple. Then I smeared a tiny bit of oil on it and pushed the new rubber hose onto it, supporting the fitting from the back side and pushing only straight on the hose. Obviously, it's safer to cut the factory hard line. But, you still must be careful to not tug on the half that goes to the manifold when connecting your catch can hoses to it.
iamdub
Full Access Member
Found this in my thread:
https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/page-19#post-1317412
The valve I got was from Lowe's and was $8. I recall finding the exact same one at Harbor Freight for a few bucks less. It's way better than having to twist that crappy T-handle while oil is pouring out.
Drok
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yeah it wold be especially since i put mine back by the firewall haha
