No PCV valve on drivers-side bank?

[NotBlake]

Went to replace my PCV valves at 50K miles, and parts department said only one PCV on our cars. I asked him what was on the other bank and he said that he didn't know but there was only one PCV valve part number and it was for the passenger side.

I did notice the valve on the passenger side was a different color (black) vs the passenger side (brown).

Thoughts? Anyone have the pass side part number or know what it is?

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[NotBlake]

Well, popped the sucker off and would you just look at that? It's just a straight hole, wild!

 

[keltymd]

I would have to say the reason is where they plumb. the passenger side plumbs in after the throttle body so it draws much more vacuum so a valve would be needed to cut back no the amount of oil sucked in where the drivers side is fed before the TB so it does not draw the vacuum levels of the PS. That also explains why most NA cars only need/want an oil air separator on the passenger bank.

 

[melwff]

The passenger side equipped with the PCV valve is exposed to the high vacuum condition's caused by the throttle body being partially or completely closed. This permits the crankcase gases to be sucked into the intake stream. These gases have to be replaced with fresh air to prevent a low vacuum situation in the crankcase. That fresh air is being sucked in through the pipe on the drivers side into the crankcase.

 

[keltymd]

The passenger side equipped with the PCV valve is exposed to the high vacuum condition's caused by the throttle body being partially or completely closed. This permits the crankcase gases to be sucked into the intake stream. These gases have to be replaced with fresh air to prevent a low vacuum situation in the crankcase. That fresh air is being sucked in through the pipe on the drivers side into the crankcase.

the funny thing is vacuum in the crank case is a good thing. Look at all the race engines they run vacuum pumps on teh crank case to reduce drag and it limits oil leakage as well.

 

[NightmareMoon]

Correct, from what I've read, some efficiency gains are to be had by maintaining a vacuum in the crankcase, and that's what the passenger side plumbing does.

The drivers side line is more to supply air instead of vent it, which is why there isn't a check valve on that side and why we don't see much if any oil / oil vapor entering the intake from that side. Its doing a different job and I guess that's why it doesn't have a check valve like the drivers side.

In stock form, this venting design works well for most driving conditions up to full throttle, where you don't have much of any vacuum to draw on. Race cars or blown applications have to use a different design, since they spend so much time at zero vacuum or positive pressure.

 

[NotBlake]

The passenger side equipped with the PCV valve is exposed to the high vacuum condition's caused by the throttle body being partially or completely closed. This permits the crankcase gases to be sucked into the intake stream. These gases have to be replaced with fresh air to prevent a low vacuum situation in the crankcase. That fresh air is being sucked in through the pipe on the drivers side into the crankcase.

This is really interesting. Thanks for the info!

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