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Old Jun 16, 2010 | 02:52 PM
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Is the PCV "valve" on the LS2 / LS3 an actual valve in the traditional sense? I am trying to determine if one is working properly.

Most systems utilize a ball-type check valve and are functioning properly if you can suck air through but not blow air out of the attached rubber line.

Does one check the LS2 / LS3 PCV's mounted on the valley cover in the same fashion? If not, how can you determine if it is functioning correctly?

Last edited by techvette; Jun 17, 2010 at 07:04 PM.
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Old Jun 17, 2010 | 07:04 PM
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bump
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Old Jun 17, 2010 | 09:33 PM
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It is just a fixed orifice to limit the air flow rate for the crankcase ventilation.
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Old Jun 17, 2010 | 09:57 PM
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No check valve.
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Old Jun 18, 2010 | 09:25 AM
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I am interpreting this as "nothing can go wrong with the PCV "valve" / system unless is is clogged?"

Correct?
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Old Jun 18, 2010 | 09:38 AM
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No valve, it's a fixed orifice. The Positive Crankcase Ventilation system on the C6 uses one line from the valley cover to behind the throttle body to remove positive pressure (blowby) from the crankcase and another line to the passenger side valve cover from in front of the throttle body to allow fresh, filtered air into the crankcase.
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Old Jun 18, 2010 | 10:09 AM
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The reason I ask is that I am trying to figure out an oil consumption issue and there is a lot coming through the PCV into the intake manifold.

With most systems, you can tell if they are working correctly by being able to suck air through them, but not be able to blow air through them. I suppose that won't work with a fixed orifice.

So being a fixed orifice, there are no moving parts in there to stop working or break, which means it really can't fail...Right?

So I guess my search for the cause continues...

Last edited by techvette; Jun 18, 2010 at 10:11 AM.
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Old Jun 18, 2010 | 10:18 AM
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What do you consider and "oil consumption issue"? If the oil ends up in the intake it's blowby (bad rings?).

My '05 used 1/2 quart of oil in 13,000 miles (4 oil changes) but when I pulled the intake to swap to a ported intake the stock intake was covered in oil. Very minimal oil use but lots of oil on the intake.
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Old Jun 18, 2010 | 10:53 AM
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Originally Posted by haljensen
What do you consider and "oil consumption issue"? If the oil ends up in the intake it's blowby (bad rings?).

My '05 used 1/2 quart of oil in 13,000 miles (4 oil changes) but when I pulled the intake to swap to a ported intake the stock intake was covered in oil. Very minimal oil use but lots of oil on the intake.
Gonna perform a leak down test on it as soon as I get a chance. It makes good compression, but is drinking at least a quart every tank of gas. I'm sure a leak down test will provide a lot of answers.
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Old Jun 18, 2010 | 11:31 AM
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Originally Posted by Driver84
Gonna perform a leak down test on it as soon as I get a chance. It makes good compression, but is drinking at least a quart every tank of gas. I'm sure a leak down test will provide a lot of answers.
If you're using a quart of oil in say 400 miles (tank of gas), you've got a bigger problem than the PCV circuit. That much oil consumption has got to be due to bad rings or bad valve seals....not sure how you can say you've got good compression, but leak down test is good next step.
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Old Jun 18, 2010 | 12:15 PM
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Consider an oil catch can
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Old Jun 18, 2010 | 12:41 PM
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Since this is my car you guys are talkin about, let me clear the air: IT IS NOT consuming one quart of oil per tank of fuel. The oil consumption is high, no doubt, but it's not at the level it's being made out to be. Also take into considertaion that it's a stroked LSX455 with no oil cooler. Engine heat also plays a part in viscosity breakdown. And since I live in Houston, TX the climate here is not condusive to larger cubic inch motors with no cooling modifications whatsoever.
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Old Jun 18, 2010 | 01:16 PM
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Pull any LS intake after 10K or so miles, and you will see oil. Do not be suprised, there is no in getting around this. This will look like a significant amount if you havent seen it before, but it is not that bad.

The best judgement is to keep track of how much oil your car is burning. According to GM, 1qt every oil change is acceptable, but I have never seen mine burn that much.

I personall do not like oil in my intake, espcially after all of my extensive modifications so I have install a catch can system to catch as much oil as I can.
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Old Jun 18, 2010 | 01:39 PM
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I was misinformed about how many miles the car had been driven since the oil was topped off. Now it looks like a more reasonable consumption number of 1 quart every 5-600 miles is the reality of it.

A leak down test will be performed shortly, followed by the addition of a catch can and an oil cooler.
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Old Jun 18, 2010 | 08:09 PM
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Install a catch can. It won't remove all oil from the intake but will keep a significant amount out.
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Old Jun 18, 2010 | 08:54 PM
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I did the same.

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Old Jun 18, 2010 | 10:07 PM
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I sure do like that catch can !

I think everyone should have one
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