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Why did you have it done twice? Was it throwing codes or running rough or just preventative?

Also, can you tell us what the cost was? Did you have the dealer chemical treatment or walnut blasting?
I consider it part of my personal regular maintenance program. I studied a lot of the issues direct injection engines of all makes and intake valve carbon is an issue with all of them since fuel doesn't pass by the intake valves. detergents in the fuel or additives can't clean the valves. I had it done at 60,000 and at 120,000. Chemical treatment done by my personal mechanic, not the dealer, who ran a camera down the intake to see how much carbon was actually on the valves. $80. If you wait until the vehicle begins running abnormally or throws a code, then the damage is already done.
 

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Here is some info to consider before modifying the PVC orifice and why it may not be a good idea. There are all kinds of remedies on the internet, but the bottom line is if you are considering this because of oil in the breather or excess oil consumption, there is already damage to your engine and the countdown clock is ticking. Also, take the time to read up on direct injection engine issues.You'll find it's an issue among all makes, not just GM, and something the industry doesn't want to talk about.

How does a positive crankcase ventilation (PCV) system work?
 

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Yes agreed, carbon is an issue across various manufacturers. Some are have made a Hybrid with Direct Injection and injecting into the intakes. I was looking at the Camaro5 Forum and one member emailed Techtron asking how their product helps reducing the Carbon Build up in Direct Injection engines. They answered saying that it works well cleaning the injector but very vague on the benefits of carbon cleaning on the valves. So, Tecthron does very little, if anything to clean the valves.
I modified the PVC on my 08 when I was having milkshake issues, ran great for another 80,000 miles.
 

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I no longer have oil in my clean air intake!!
It is bone dry clean.
By replacing the Oem oil cap with one way vented $80 cfm oil cap, I no longer get any oil in my clean air intake.

Oil gets into clean air intake when crankcase sees positive pressure from piston blowby
And when intake manifold vacuum is too low to keep the crankcase in a vacuum state
When the crankcase see positive pressure
is when crankcase gunk is pushed out the clean side PCV breather hose and into the clean air intake
But, With the cfm oil cap, when crankcase sees positive pressure, the pressure vents out the cfm oil cap, thus keeping crankcase at zero pressure.
Thus with no positive pressure in crankcase crankcase, crankcase gunk does not get pushed into clean air intake.
Since the cfm oil cap is a one way vent, at idle, when intake manifold vacuum is say 10 psi ( of vacuum) the crankcase is also in a vacuum state, and the cfm oil cap is seals shut.

Then as designed the cleanside PCV breather hose lets clean air into crankcase.
 

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Yes agreed, carbon is an issue across various manufacturers. Some are have made a Hybrid with Direct Injection and injecting into the intakes. I was looking at the Camaro5 Forum and one member emailed Techtron asking how their product helps reducing the Carbon Build up in Direct Injection engines. They answered saying that it works well cleaning the injector but very vague on the benefits of carbon cleaning on the valves. So, Tecthron does very little, if anything to clean the valves.
I modified the PVC on my 08 when I was having milkshake issues, ran great for another 80,000 miles.
I no longer have oil in my clean air intake!!
It is bone dry clean.
By replacing the Oem oil cap with one way vented $80 cfm oil cap, I no longer get any oil in my clean air intake.

Oil gets into clean air intake when crankcase sees positive pressure from piston blowby
And when intake manifold vacuum is too low to keep the crankcase in a vacuum state
When the crankcase see positive pressure
is when crankcase gunk is pushed out the clean side PCV breather hose and into the clean air intake
But, With the cfm oil cap, when crankcase sees positive pressure, the pressure vents out the cfm oil cap, thus keeping crankcase at zero pressure.
Thus with no positive pressure in crankcase crankcase, crankcase gunk does not get pushed into clean air intake.
Since the cfm oil cap is a one way vent, at idle, when intake manifold vacuum is say 10 psi ( of vacuum) the crankcase is also in a vacuum state, and the cfm oil cap is seals shut.

Then as designed the cleanside PCV breather hose lets clean air into crankcase.
I agree that the above measures can give some relief. Unfortunately, venting any crankcase gas directly into the atmosphere is illegal. I won't recommend anything that is illegal, as is modifying the orifice in the pcv low rpm circuit. My mechanic (California) has had to fail several GM vehicles in the smog test because they did not change the filler cap back to the stock unit. The fact that there is enough piston blow-by to push oil into the clean air intake indicates worn piston rings.

I am curious, did both of you use synthetic oil from day one?
 

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I have been reading all the posts on Traverses and oil consumption. Had me regretting I bought a Traverse but I am a Chevy guy! I have purchased a new PCV orifice ( I know it;s not a PCV valve), new AC Delco hoses to PCV, and prepared to install a oil catch can. In all the posts of other Lambda products I haven't seen specific instructions on where I attach the hoses at the PCV area. Is the "dirty side the hose at right (rear) valve cover or a top of intake manifold. Either way I just pulled the flexible billows hose with oil catch area from air cleaner to throttle body and found it totally dry! No oil. i have a 2016 2LT with 39,000 miles. I wanted to pass this along that MAYBE my generation of Traverses have had the correction to clean up the crankcase fumes fixed. Hoping I don't get the intake valve/cylinder scoring issues.
 

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I agree that the above measures can give some relief. Unfortunately, venting any crankcase gas directly into the atmosphere is illegal. I won't recommend anything that is illegal, as is modifying the orifice in the pcv low rpm circuit. My mechanic (California) has had to fail several GM vehicles in the smog test because they did not change the filler cap back to the stock unit. The fact that there is enough piston blow-by to push oil into the clean air intake indicates worn piston rings.

I am curious, did both of you use synthetic oil from day one?
CFM's website implies they are legal in all states except CA.
 

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CFM's website implies they are legal in all states except CA.
I can't see how it would be if you are venting the crankcase to atmosphere.

I'd also be concerned about a vented cap on a mass airflow car, understand it's supposed to flow only one way but unmetered air entering the crankcase is usually going to tick off the ecm and throw codes at least.
 

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CFM's website does not seem to list an oil cap for the Traverse. Did you get the "universal" one?
Gm has pretty much standardized certain components to get economies of scale.

My 2 cents...
The cfm oil cap I use on traverse is the same size as the one I use on my equinox. ... which I believe is the same size as a number of engines... the LS1,LS2....

On my 2.4 liter ecotec equinox engines,
crankcase pressure is high even at idle, yup, even at idle, the engine is venting through this cap.
At idle my equinox intake manifold pulls a vacuum of about 10 psi, as measured with a scan tool.
The PCV system is so crappy on the equinox, that in winter this 2.4 liter engine fails from crankshaft rear main seal failure. For that reason I first used the cfm oil cap.

On my traverse and V6 equinox,
at idle the vacuum in crankcase sucks the check valve of this oil cap shut, so no air is sucked into crankcase,
so if does not mess up your fuel trims.
It only lets air out of crankcase when the crankcase sees positive pressure so it will. Not mess up fuel trims.
Normally, crankcase should only be under positive pressure during WOT,when intakemanifold vacuum is not sufficient To overcome piston blowby.
 

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ThreeNox, there may be something wrong with you Equinox if you are only seeing 10inHg in your intake. What PID are you looking at on your OBDII tool. Vacuum is not measured in PSI.

These PCV systems using an orifice does not work the same way as system with metered PCV valve. In valve system, flow is one way. With orifices, crankcase gases are drawn through the orifice at idle and slight throttle. When the throttle is opened more, under engine load, crankcase gases are drawn out through the fresh air side of the PCV system and through the throttle body. You should have vacuum in the crankcase at WOT, as air flow is greatest in the air plenum and the hose connecting the air plenum to the crankcase is much larger.

How are you measuring crankcase pressure/vacuum?
 

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I can't see how it would be if you are venting the crankcase to atmosphere.

I'd also be concerned about a vented cap on a mass airflow car, understand it's supposed to flow only one way but unmetered air entering the crankcase is usually going to tick off the ecm and throw codes at least.
Nhrata01, these caps are sold for street legal rods and offroad which are exempted from emissions. CFM performance has not tested these for compliance with emission standards. They are not recommended in cold climates by CFM, as they can freeze. They only reccommend use when the engine and cap are at full operating temps. They contain a lightweight nylon ball, that vents at the slightest pressure. Any crankcase will have pulse of pressure and vacuum, as it is normal condition.
 

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I can't see how it would be if you are venting the crankcase to atmosphere.

I'd also be concerned about a vented cap on a mass airflow car, understand it's supposed to flow only one way but unmetered air entering the crankcase is usually going to tick off the ecm and throw codes at least.
Venting to the atmosphere has been illegal federally since at least 1977. 20% of all emissions come from the crankcase. Here is the downloadable book from the EPA outlining PVC systems.

 

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Venting to the atmosphere has been illegal federally since at least 1977. 20% of all emissions come from the crankcase. Here is the downloadable book from the EPA outlining PVC systems.

All this being said, if your state doesn't have annual vehicle smog emissions testing (some are every 2 years or random) then your probably not going to get caught. And even if you have inspections, then you can change it back before inspection unless you get chosen at random. But hey, I think everyone can agree clean air is nice and do you really want to contribute to more air pollution?

The industry was caught off guard by the gasoline direct injection issue. Most people did not run synthetic oils from the beginning and standard motor oil has a much lower flash point which contributes to the vapor in the crankcase that eventually winds up as hard deposits on the intake valve. I was actually unaware of the issues until I read about it here on this forum and then went and researched it. It didn't affect us because I ran synthetic oil from the beginning and we had about 60,000 when I became aware of it, got with my mechanic to check out the vehicle since I usually do all my own service until there is a situation that I need help with. We came up with a maintenance plan to take care of it -- hopefully. Nearing 130,000, so far, so good. No adding oil between changes.

Good Luck, All
 

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Manufacturers were too confident in their introduction to Oil Life Monitors, underestimated fuel dilution and did not consider the affects of GDI fuel soot, which is not captured by the typical full flow filter.

Thanks for the PCV document. Although it was written in 1977, it give a background and function with closed loop system with variable valve. Newer cars have done away with variable valves that are prone to failure, stuck open or closed. They now used fixed orifice to provide air flow in the crankcase at idle, and at load and open throttle they use the venturi affect and higher blowby to draw gases out of the crankcase through the air plenum and throttle body. People often see the presence of oil and water in the air plenum as a malfunction. This is normal up to a point, and many designs include a basic air/oil separator. The problem is that manufacturers do not tell customers about this separator and the need to clean and empty. If you are getting large amounts of water and emulsified oil then you may have piston ring and cylinder blow-by problem.

What is your maintenance plan and steps to mitigate the problems.
 

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Manufacturers were too confident in their introduction to Oil Life Monitors, underestimated fuel dilution and did not consider the affects of GDI fuel soot, which is not captured by the typical full flow filter.

Thanks for the PCV document. Although it was written in 1977, it give a background and function with closed loop system with variable valve. Newer cars have done away with variable valves that are prone to failure, stuck open or closed. They now used fixed orifice to provide air flow in the crankcase at idle, and at load and open throttle they use the venturi affect and higher blowby to draw gases out of the crankcase through the air plenum and throttle body. People often see the presence of oil and water in the air plenum as a malfunction. This is normal up to a point, and many designs include a basic air/oil separator. The problem is that manufacturers do not tell customers about this separator and the need to clean and empty. If you are getting large amounts of water and emulsified oil then you may have piston ring and cylinder blow-by problem.

What is your maintenance plan and steps to mitigate the problems.
I am not changing anything I am doing. It seems to work. Using synthetic oil from the start seems to prevent the issue in my case. 125,000 miles without using more than a few ounces between changes. In general, a Haynes or other aftermarket manual for the various brands lists cleaning and emptying the separator in the maintenance section for those so equipped. Neither one of my vehicles has one. No one this day and age should do their own oil changes and other basic maintenance without a manual of some kind. My particular manual was written in 2012 before the Direct Injection issues became the issue it is today. The more current manual does recommend a periodic intake valve cleaning procedure to be done by a professional. The manufacturer does tell it's dealers about revised service/repair procedures through TSBs (Technical Service Bulletins) I'll post the link to the a TSB website where all can view the various TSBs for their vehicles. While the manufacture does let it's dealers know about these maintenance issues, for those of us who do our own maintenance, it's up to us to research these issues.

Here is a TSB website: Chevrolet Traverse Technical Service Bulletins (TSBs)
 
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