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Discussion Starter #1
4cyl. I was contemplating putting a catch can in line from the crankcase to the air intake. Looking into it I realized, this line is used to suck filtered air from the airbox into the crankcase, not vent from crankcase to air intake. I've noticed water in this line on many occasions so I decided today in the freezing temps to take a look, that line was filled with water which at this point was frozen, blocking any airflow.
I know with these cars the moisture is common in cold climates. I'm thinking either A) just run a breather filter on the line, the line would turn down instead of up, allowing any built up moisture to drain out through the breather. Or B) install the catch can below the crankcase vent to catch any water, keeping it out line so it can't freeze over.
 

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4cyl. I was contemplating putting a catch can in line from the crankcase to the air intake. Looking into it I realized, this line is used to suck filtered air from the airbox into the crankcase, not vent from crankcase to air intake. I've noticed water in this line on many occasions so I decided today in the freezing temps to take a look, that line was filled with water which at this point was frozen, blocking any airflow.
I know with these cars the moisture is common in cold climates. I'm thinking either A) just run a breather filter on the line, the line would turn down instead of up, allowing any built up moisture to drain out through the breather. Or B) install the catch can below the crankcase vent to catch any water, keeping it out line so it can't freeze over.

not sure what you mean by "crankcase vent" on the 2.4L engine? Can you show where yo mean on a picture or diagram?

The 2.4L has an internal PCV orifice in the cylinder head. So no easy way to install a catch can in the proper place.

And a "breather" will not work either since it will trigger a vacuum leak and DTC as well as casue the engine to run rich.
 

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Discussion Starter #3 (Edited)

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I see, but that line does not route air FROM the crankcase into the air box, but supplies fresh filter air from the air box into the valve cover area and into the engine.
The air then circulates into the crank case and is sucked into the intake manifold via the tiny hole (PCV orifice) that gets drilled out as shown in the TSB.

That tiny hole is what usually get clogged with both oil/carbon deposits and water vapor in winter. . . when it will freeze and cause pressure to build up in the crankcase which then will blow out the rear main seal.

If the idea is to try to remedy any crankcase pressure IF the PCV orifice freezes or gets clogged, then a pressure relief "fail safe" valve might be a better choice. That way, even if the intake air line or PCV orifice gets clogged/frozen .. . crankcase pressure can be released and not damage the main seal. When the engine gets warm enough, any water will melt and the system will return to normal operation - - - meaning a slight vacuum in the crankcase rather then pressure because of a clogged PCV path.
 

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That's interesting. Because with mine there is an oily sludge that accumulates in the air intake assembly right where that tube connects. Not nearly as bad this winter as it was last winter prior to the engine rebuild. For something that os supposed to suck in air, I was sure getting alot of the opposite.

Pictures from last year.
 

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Discussion Starter #6
That's interesting. Because with mine there is an oily sludge that accumulates in the air intake assembly right where that tube connects. Not nearly as bad this winter as it was last winter prior to the engine rebuild. For something that os supposed to suck in air, I was sure getting alot of the opposite.

Seems to be common. And yes I do know, as do you that this line should not be leaking into the air intake but it does happen. How serious of a problem, I'm not sure but I do know watery sludge through the air intake is not ever a good idea, not to mention a collection of it right where that line connects, I've drained my air intake a few times, why is that a thing, that should never have to be done. The orifice is thought of as a one way valve but is more prone to staying open in certain circumstances, my assumption why there is sometimes a "backflow" into the air intake.
When I get it tackled I'll post some pics and results.
 

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That's interesting. Because with mine there is an oily sludge that accumulates in the air intake assembly right where that tube connects. Not nearly as bad this winter as it was last winter prior to the engine rebuild. For something that os supposed to suck in air, I was sure getting alot of the opposite.

Pictures from last year.
Under heavier throttle conditions, or when coasting down hill or up to stops, back flow will occur in the PVC air intake tube. Happens in all PCV systems.

That yellow sludge like stuff is oil/water emulsion from oil and water vapor that forms in cold or very humid weather conditions. Not much you can do about it. In newer engines they have both increased the diameter of the tubes and orifices and run the PCV path deeper into the engine internals to keep things warmer. The larger diameter tubes and path results in slower air flow and less cooling of the vapors. The deposits still form, but end up in the oil so freezing and deposits are less likely to form.
The downside is. .. change the oil more often in cold weather. I always change oil in October and again in January some time no matter the number of miles on the oil and filter. I reason it is worth it rather than having all the moisture build up.

Also, here is another idea. Buy another oil filer cap, drill a hole into it, and install one of these. * See pictures attached below. *
It won't reduce the moisture and crud build up, but if it does get very cold and the PCV orifice or path freezes or gets clogged, this pressure relief valve in an oil filler cap will release built up blow by pressure in the crankcase and prevent main seal blow out. . . . in theory. Run the modified oil filler cap in the cold winter months. Put the stock cap back on in summer.
 

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Discussion Starter #8
I see, but that line does not route air FROM the crankcase into the air box, but supplies fresh filter air from the air box into the valve cover area and into the engine.
The air then circulates into the crank case and is sucked into the intake manifold via the tiny hole (PCV orifice) that gets drilled out as shown in the TSB.

That tiny hole is what usually get clogged with both oil/carbon deposits and water vapor in winter. . . when it will freeze and cause pressure to build up in the crankcase which then will blow out the rear main seal.

If the idea is to try to remedy any crankcase pressure IF the PCV orifice freezes or gets clogged, then a pressure relief "fail safe" valve might be a better choice. That way, even if the intake air line or PCV orifice gets clogged/frozen .. . crankcase pressure can be released and not damage the main seal. When the engine gets warm enough, any water will melt and the system will return to normal operation - - - meaning a slight vacuum in the crankcase rather then pressure because of a clogged PCV path.
Correct, I am aware that line does not vent to the air intake, at least isn't supposed to. The tiny hole in the intake manifold will be checked if I feel it needs to be, more than likely a good idea regardless. I currently do not have any oil consumption issues at 70k miles, last change had 5qts drain out. My concern at this point is the orifice and line holding excess moisture and freezing, thus not allowing any air to enter at startup. The 2 ideas I posted above would eliminate any standing water in the line preventing ice form blocking this. I def appreciate the clarification on the other end of the pcv system as well.
 

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Discussion Starter #9
That's interesting. Because with mine there is an oily sludge that accumulates in the air intake assembly right where that tube connects. Not nearly as bad this winter as it was last winter prior to the engine rebuild. For something that os supposed to suck in air, I was sure getting alot of the opposite.

Pictures from last year.
Under heavier throttle conditions, or when coasting down hill or up to stops, back flow will occur in the PVC air intake tube. Happens in all PCV systems.

That yellow sludge like stuff is oil/water emulsion from oil and water vapor that forms in cold or very humid weather conditions. Not much you can do about it. In newer engines they have both increased the diameter of the tubes and orifices and run the PCV path deeper into the engine internals to keep things warmer. The larger diameter tubes and path results in slower air flow and less cooling of the vapors. The deposits still form, but end up in the oil so freezing and deposits are less likely to form.
The downside is. .. change the oil more often in cold weather. I always change oil in October and again in January some time no matter the number of miles on the oil and filter. I reason it is worth it rather than having all the moisture build up.

Also, here is another idea. Buy another oil filer cap and install one of these. It won't reduce the moisture and crud build up, but if it does get very cold and the PCV orifice or path freezes or gets clogged, this pressure relief valve in an oil filler cap will release built up blow by pressure in the crankcase and prevent main seal blow out. . . . in theory.
With the backflow into the air intake containing water and all, how bad is it for the motor? The air intake contains what appears to be essentially a 'compartment' where excess water builds up over time, I can only imagine this leaking out down through the tb and into the intake manifold then coating the valves. This built up compatment of water can only hold so much, any kind of driving will cause it to splash around and leak further into the intake.
 

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With the backflow into the air intake containing water and all, how bad is it for the motor? The air intake contains what appears to be essentially a 'compartment' where excess water builds up over time, I can only imagine this leaking out down through the tb and into the intake manifold then coating the valves. This built up compatment of water can only hold so much, any kind of driving will cause it to splash around and leak further into the intake.

Yes, that could happen if enough built up in there. Not really likely and they seem to have designed it with it in mind to control that. These intake "resonators" or baffles all get oil film built up over time as well. Car makers don't say to clean these, but at least every year it would be good to remove it from the engine to run some strong detergent cleaner and hot water in there, slosh it around and let it sit for awhile, then rinse and thoroughly dry it. I just had our daughters 2009 Saturn 2.4L air intake off and it was pretty coated with oily crud inside of it. Surprisingly, the throttle body did not have any visible oil on it. But I did a throttle body clean anyway. The engine needed a new camshaft actuator solenoid.
 

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The 2 ideas I posted above would eliminate any standing water in the line preventing ice form blocking this. I def appreciate the clarification on the other end of the pcv system as well.
The problem has never been water freezing in the supply hose from the air box to the valve cover. The problem is the orifice freezing and now blow by pressure building up in the crankcase.
If the air supply hose did happen to clog it would just result in more vacuum as long as the PCV orifice was not clogged or frozen with moisture.

So, any sort of breather on the air supply hose would not help much with anything. Note, venting that hose with a breather to atmosphere would trigger a DTC since it essentially would result in a MAF sensor bypass allowing unmetered air into the engine.
 
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Discussion Starter #12
The 2 ideas I posted above would eliminate any standing water in the line preventing ice form blocking this. I def appreciate the clarification on the other end of the pcv system as well.
The problem has never been water freezing in the supply hose from the air box to the valve cover. The problem is the orifice freezing and now blow by pressure building up in the crankcase.
If the air supply hose did happen to clog it would just result in more vacuum as long as the PCV orifice was not clogged or frozen with moisture.

So, any sort of breather on the air supply hose would not help much with anything. Note, venting that hose with a breather to atmosphere would trigger a DTC since it essentially would result in a MAF sensor bypass allowing unmetered air into the engine.
Disconnected the line at the airbox, air is blowing out of the line (so towards the air intake) short consistent puffs.
I went on a 15 mile drive with it disconnected, no codes, no hesitation (code could possibly take a few cycles to show up)
On top off the engine cover (surrounding area under the disconnected line) was a 'puddle' of now frozen water.

With venting to atmosphere, how is the air metered going into that line. (Air goes past the maf, but how does it know how much air is going to the tb and how much through that line? Also, with that line connected to the intake, wouldn't the intake create a vacuum, pulling air through it? Not meant to question your understanding or to sound like a smart a*
 

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If you plug the air hose hole on the air box, then possibly no DTC would be logged. It would be best to connect a OBDII scanner to the port and monitor engine operation and see of pending codes pop up.

I would try holding your thumb over the end of the hose with engine running, while someone steps on the gas pedal. You should then feel vacuum on the air hose, unless the PCV orifice is already partially or mostly clogged.
 

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Discussion Starter #14
If you plug the air hose hole on the air box, then possibly no DTC would be logged.

I would try holding your thumb over the end of the hose with engine running, while someone steps on the gas pedal. You should then feel vacuum on the air hose, unless the PCV orifice is already partially or mostly clogged.
Gotcha, awesome thanks.
 

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So there is really nothing I can do about this? I don't feel comfortable 'altering' anything under the hood that the dealer could see when opening the hood. (oil cap) - I warm the car up everyday its below 30 degrees. I am starting to get quite a bit of build up where the tube clicks into the intake baffle.
 

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Discussion Starter #16
So there is really nothing I can do about this? I don't feel comfortable 'altering' anything under the hood that the dealer could see when opening the hood. (oil cap) - I warm the car up everyday its below 30 degrees. I am starting to get quite a bit of build up where the tube clicks into the intake baffle.
Don't hold me too it lol. I currently have a breather filter on the line and a rubber grommit plugging the small hole in the air intake. I'll get some pics when I more securely fit a breather on (more of a finished product)
I've done the same on other cars (not gdi) with no issues. I'm gonna see how it holds up over the next few days, check under oil cap. If I see an improvement I'll leave it, worst case I connect the line back to factory.
 

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Discussion Starter #17
So there is really nothing I can do about this? I don't feel comfortable 'altering' anything under the hood that the dealer could see when opening the hood. (oil cap) - I warm the car up everyday its below 30 degrees. I am starting to get quite a bit of build up where the tube clicks into the intake baffle.
Don't hold me too it lol. I currently have a breather filter on the line and a rubber grommit plugging the small hole in the air intake. I'll get some pics when I more securely fit a breather on (more of a finished product)
I've done the same on other cars (not gdi) with no issues. I'm gonna see how it holds up over the next few days, check under oil cap. If I see an improvement I'll leave it, worst case I connect the line back to factory. I'd put money on it that the factory setup causes milky oil dripping into the air intake, it's not something that I want to continue having.
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Note, venting that hose with a breather to atmosphere would trigger a DTC since it essentially would result in a MAF sensor bypass allowing unmetered air into the engine.
Lol. What if I told you that I once accidentally left the pcv breather hose unplugged from the air intake cover.
Did that for an entire day.
I finally discovered it when, for kicks, I hooked my scanner and observed the fuel trim at +20%!
Realized in short order my goof.
There was no cel. No pending codes either.
??????
 

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Lol. What if I told you that I once accidentally left the pcv breather hose unplugged from the air intake cover.
Did that for an entire day.
I finally discovered it when, for kicks, I hooked my scanner and observed the fuel trim at +20%!
Realized in short order my goof.
There was no cel. No pending codes either.
??????
+20%


Wow. . . there went the MPG I imagine? And maybe future cat damage since it would be running rich.
 
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