PCV House/s? and Catch Can

[Ben Hinz]

So I'm gearing up on getting ready to install the updated Valve Cover (GM - 12570427) and Catch Can (Moroso - 85481) on my 09 Tahoe 5.3L Flex. My question is, I know there's the PCV Tube on the driver's side. But there is also a tube that comes off the front of the Passengers valve cover. In my case, that tube goes to my S&B Intake. Is that a PCV tube too? I'll attach some pictures from AllData and a video I shot. It's a bit hard to follow. Holding a flashlight and filming, while making sure there's light on it and in focus is harder then it seems. Also, the second AllData photo of the passenger's side shows the tube I'm referring to, except it goes to the side of the motor somewhere and mine goes to the Air Intake tube. I don't recall if mine went to the side if the motor as well. Now, Let's say this tube is a second PCV type thing, can I use a T-Fitting and splice this into my catch can?

-Ben

Standard PCV Tube


Unkown Tube

 

[Brian Wilson]

Do the drivers side tube and ignore the other. 90% of intake oil is from the drivers side tube. I had a catch can on both sides. The passenger side never filled in 2 years of driving.

 

[kbuskill]

The drivers side is referred to as the dirty side. The passenger side actually sucks air in from the intake tube where as the drivers side is hooked to a vacuum port and sucks dirty air/oil out of the drivers side valve cover.

Nothing should be getting pushed out of the passenger side into the intake tube.

 

[NGAneer]

I wouldn't worry about it. If you do tee into the PCV connections for the catch can, DO NOT reconnect any of the tubing back to you're intake. You'd effectively be bypassing your throttle body and introducing unmetered air.

 

[Jason_S]

I wouldn't worry about it. If you do tee into the PCV connections for the catch can, DO NOT reconnect any of the tubing back to you're intake. You'd effectively be bypassing your throttle body and introducing unmetered air.

This is not correct. You do not "tee" into the PCV line for a CC. It goes in-line. The CC should be sealed and will not cause an air leak.

 

[Brian Wilson]

I think he means tee both hoses together in front of the catch can. If he did that, and hooked up the outlet of the catch can to the intake it would send air to the intake until the vacuum in the crankcase meets equilibrium with the engine vacuum. In our application, it would create a vaccume in the oil system. Since no new air can be brought into the system. So if you engine is pulling 15 psi vacuum , your oil system would be at 15 psi vacuum. It would essentially turn your crank case into a giant vacuum canister. Also, to get a good air full ratio, you would have to plug the 1/4 inch barb on the intake tube since it is downstream of the maf sensor and will seriously mess up your ratio being unmetered air.

That being said, that is the absolute worst idea. It is completely incorrect to install a catch can like that.

If you want to install a catch can, on our trucks, pull the pcv tube from the intake and drivers side valve cover rear. Throw it away.
Mount your catch can somewhere you can easily monitor it and empty it. I chose the bracket the hood strut attaches to on the firewall.
Attach a 3/8 fuel hose to the valve cover barb and the inlet of the catch can. No hose clamps are required if using the 3/8 hose.
Attach a 3/8 hose from the catch can outlet to the vaccume port on the intake.

Done. Takes about 5 minutes after you mount the catch can. Keep the lines away from the exhaust manifolds and empty the catch can when it is half to 3/4 full. If you don't empty the catch can, you are not getting the benifits of the can. If you haven't biught a can yet, I seriously recomend getting a large clear catch can.

 

[NGAneer]

I think he means tee both hoses together in front of the catch can. If he did that, and hooked up the outlet of the catch can to the intake it would send air to the intake until the vacuum in the crankcase meets equilibrium with the engine vacuum. In our application, it would create a vaccume in the oil system. Since no new air can be brought into the system. So if you engine is pulling 15 psi vacuum , your oil system would be at 15 psi vacuum. It would essentially turn your crank case into a giant vacuum canister. Also, to get a good air full ratio, you would have to plug the 1/4 inch barb on the intake tube since it is downstream of the maf sensor and will seriously mess up your ratio being unmetered air.

That being said, that is the absolute worst idea. It is completely incorrect to install a catch can like that.

If you want to install a catch can, on our trucks, pull the pcv tube from the intake and drivers side valve cover rear. Throw it away.
Mount your catch can somewhere you can easily monitor it and empty it. I chose the bracket the hood strut attaches to on the firewall.
Attach a 3/8 fuel hose to the valve cover barb and the inlet of the catch can. No hose clamps are required if using the 3/8 hose.
Attach a 3/8 hose from the catch can outlet to the vaccume port on the intake.

Done. Takes about 5 minutes after you mount the catch can. Keep the lines away from the exhaust manifolds and empty the catch can when it is half to 3/4 full. If you don't empty the catch can, you are not getting the benifits of the can. If you haven't biught a can yet, I seriously recomend getting a large clear catch can.

You caught what I was throwin'

 

[NGAneer]

This is not correct. You do not "tee" into the PCV line for a CC. It goes in-line. The CC should be sealed and will not cause an air leak.

Just a misunderstanding. He was asking about the passenger side pcv hose which is not really a good idea to fool with at it's not a "dirty" portion of the PCV system anyway.

 

[Brian Wilson]

Yes the drivers side hose is the pcv side. It is the dirty side

 

[NGAneer]

Corrected. I meant the passenger/intake tube side. I need more coffee.