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Discussion Starter · #1 ·
Background:

I own a stock 2014 2LT (1.4T, automatic) with 55,500ish miles on it. I live in NY. It is bloody cold here. I accidentally broke the PCV tube connecting the intake piping (right at the turbo) to the intake manifold when cleaning up oil spray caused by a bad o-ring on the oil dipstick. So I sucked it up and paid the $70 for the part from the stealership.

When I replaced the pipe today, I found there was an abundance of oil in it as well as down into the turbo intake. I mean, the pipe dripped oil when I took it off. I don't feel like this is normal and wanted some thoughts on this.

Side note: I have recently had valve cover and gasket replaced due to fault as well as waterpump replacement, and am getting sick of constant trips to the dealer with issues for this car. My patience with it is running thin...
 

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When the valve cover leaks sucks in air, it causes a lot of oil to be pulled through the PCV system, and that's what your seeing in the intake.

There is a technical bulletin that mentions before a valve cover is replaced the tech is to also inspect the check valve in the intake manifold. If this check valve is not seating high velocity air will be pulled through the valve cover. Potentially rupturing the relief valve again.

I believe this relief valve would be on the opposite end of the tubing that you just replaced. The connection at the intake manifold. Maybe 1" diameter.

A few drips of oil I wouldn't be worried about. A few tablespoons might be more of a concern. A very small amount of oil staining will be present when looking down into the inlet side of the turbo. I noticed this when I changed the air filter at 47,000 miles.

The inspection for the check valve is to remove that PCV line at the intake and look down into the intake. It may require a "Q tip" if it's really oilly, but you should be able to see the orange rubber check valve.

If it's not there, you may have to have the intake replaced.

There's threads on that.. You'll have to search for them. If you have significant oil in the intake then there's a good chance you're pulling a lot of airflow through the valve cover. This shouldn't be present if the check valve in the intake is sealing properly and the rupture disk in the valve cover is sealed.
 

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Discussion Starter · #3 ·
So take the intake manifold side of the PCV pipe I just replaced back off and look into the now exposed port on the intake manifold for signs of a check valve. Is that correct?
 

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So take the intake manifold side of the PCV pipe I just replaced back off and look into the now exposed port on the intake manifold for signs of a check valve. Is that correct?
yes but you may have to wipe it with a q tip to see it as there may be oil covering it making it hard to see. A flashlight would help too.
 

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Positive Crankcase Ventilation didn't come out until the late 50's early 60's, until then a breather pipe was used in all engines. Piston that goes up creating compression also goes down into the crankcase doing the same thing, but in the crankcase plus piston ring blowby.

Taking your foot off the gas and using vehicle inertia to slow you down, did exactly the opposite, creates a vacuum in the crankcase to suck up dust and dirt off the road. Ha, when overhauling an engine in these cars, needed a shovel to pick up all that muck in the crankcase, and also in the valve covers with overhead valves.

When you did hit the gas with an old engine, black smoke would pour out of the breather pipe, who cared, engine still ran, would see many vehicle on the road like this.

So that breather pipe was replaced with a hose, going from the crankcase back into the intake manifold, on an OVV engine, also opened to the crankcase, this is where that hose was placed. But have a situation where the intake manifold pressure was greater than the crankcase that would blow the air/fuel into the engine oil, not good, so a check valve was installed to prevent this, flow can only occur from the crankcase to the intake manifold. And this is all that a PCV valve is, a check valve.

Ha, guys would shake it, if it rattled would be okay, not very bright, right way to check it was to blow into the direction toward the intake manifold, should blow free, other way, should not leak at all. Use to be a one buck valve, but since it was carrying all the crap from the crankcase, would get sticky, a blast of choke and carb cleaner would get it working again. Was good to do this every couple of thousand miles or so. Or your engine oil would be deleted with gasoline, not good either.

Is there a better way? Apparently not after some odd 50 years. Keeping your engine clean with Seafoam does help, still get carbon buildup on the piston rings, letting more blowby get through. And returning this crap back into the intake manifold really wasn't that bad until they installed fuel injectors, that crap builds up on the face of the injectors affecting the spray pattern. In this respect, carburetors had it all over fuel injectors. If the return was to the base of the carb, some brains thought it would be good to return that hose to the air cleaner, that really messed up the carb with crap.

GM for years was a little smarter in returning that hose to the base of the now throttle body, but don't feel they were very wise in returning this hose actually after the air cleaner and directly into the turbo, Already had a sticky vane in my TB, was very slow in closing when I released the gas pedal, had to clean that with choke and carb cleaner and appears to be a periodic job.

Wonder if the engineers that did it this way are reading this, apparently they are not aware of the 55 some odd year history of this valve. The PCV valve was metal, cheap using just a plain neoprene hose. Corrugated plastic when you think about it is nothing short of stupid, restricts air flow. And 70 bucks for this POS is nothing short of outrageous, and becomes very brittle in cold temperatures.

This is definitely another item that should be added to that 150,000 mile/10 year warranty like they did on several other items.

And yes, this PVC is pulling 19"/Hg from the crankcase, actually from the camshaft cover, same thing, and will also pull some engine oil from it. And yes, this oil is getting back into the combustion chamber causing a chain reaction even further adding more carbon build up to the piston rings, really a very nice self destructive mechanism.

Find it a lot easier to discuss issues like this to other engineers, oh, I didn't think about this, worse people to discuss issues like this is to marketing and your Chevy service manager.
 

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Discussion Starter · #6 ·
Thank you for your replies. I looked down in the intake manifold through that port where the PCV pipe attaches and it was pretty grimey as well. I'll try and dab some up with a cotton swab and look again, but it sounds like I'll at the very least be stopping by to discuss the matter with the service department. Thank you for your help.
 

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Adding a can of Seafoam to a full tank of gas sure helps in keeping the inside of the engine clean. And this includes the PCV hose, a lot less blowby to recirculate.

With 155 different blends of gasoline mandated by the EPA, really hard to know what you are getting along with gas pipeline mix ups. Another is EGR, exhaust gas recirculation, Least the Cruze does not have this valve to be concerned about, if it doesn't open, can burn up your engine due to the extremely high combustion temperature of unleaded gas. But leaded gas gives other more serious health problems. Just people nuts, makes them aggressive, and get into politics really messing up the country.

Cruze closes the exhaust valves sooner to keep some of that crap in there, more carbon build up.
 

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This is installed on 1.4 T but remains the same on other turbo engines.

I have been looking at the turbo intake some time ago, and after 40000 km, it was brown and had a light coat of oil from the PCV, therefore I was inspired to install a catch can system but not willing to drop the 100 plus for it. Therefore I applied some navy improvisation to fabricate a knock off for about 40 dollars. Of note it is a modified compressed air filter and clear pressure hose with two fitting and clamps, using the stock PCV hose ends after I pulled the PCV hose apart. It has been installed for over 400 kms now and I am already seeing the inlet hose interior changing colour compared to the outlet to the turbo intake which I still clear. It is operating as a suitable catch can.

I am surprised by the volume of condensate, considering that the car is started driven 6 miles, shutdown for 8 hours and driven back, meaning very few cold start short runs.
 

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I am surprised by the volume of condensate, considering that the car is started driven 6 miles, shutdown for 8 hours and driven back, meaning very few cold start short runs.
That sounds like a cold run to me, especially considering how long these 1.4T's take to warm to full operating temperature (and the oil longer yet!). A good highway run or 30-40 minutes of city driving is what it really takes to get oil to full operating temp.

My dad does about the same with his car, a 5 mile trip to work, and there's all kinds of yellow sludgy stuff (condensation) in the PCV hoses in the winter. Got a picture from him one day saying "What's wrong with my car?"

 

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I am surprised by the volume of condensate, considering that the car is started driven 6 miles, shutdown for 8 hours and driven back, meaning very few cold start short runs.

I meant 60 miles vice 6, which might not be a factor after all.

I was sitting in the car this morning on my way into work thinking about the condensate.

The oil should be free of water that needs to be boiled off so to speak during that drive.

According to reference below.

One thing to think about is the fact that a well built, well tuned engine for emissions would might have 0.5 % air volume blowby and a worn engine would be around 3%, some of which is actually water vapor from the combustion process.

The short run with the cold block and piping would be enough to form some condensate in the engine like the picture that Justin provided, as it would be trapped in the low velocity locations similar to my catch can.

I doubt that the catch can will ever get hot enough to evaporate the water that I trap.

http://www.106rallye.co.uk/members/dynofiend/breathersystems.pdf
 

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Cleaning the PCV hose and check valve around every 40K miles or so is not as bad as the huge number of times I have to mop the kitchen floor.

Ha, everything is relative.
 
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