Oil catch can options

[wsteele]

well it's connected to the intake tube before the throttle body so it's definitely under vacuum but I can feel it sucking air into the engine through that line

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.

 

[wsteele]

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]

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

 

[wsteele]

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.

 

[HD_LS]

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

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]

another question I had was I see that the pcv runs to the middle of the intake manifold but the reason I picked up the catch can was to try and help out the build up I keep getting on my throttle body. is there another line that I could tap into?

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]

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.

do you think I would be able to tap both lines into one catch can or would it choke everything up?

 

[iamdub]

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.

I agree with this.

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.

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!

do you think I would be able to tap both lines into one catch can or would it choke everything up?

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]

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]

I agree with this.




I agree with this, as well.




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.

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.