# Yet another 1.4T PCV issue, massive amounts of oil in intake



## dieselshadow (Nov 27, 2016)

Hello, new guy here. I've lurked and been greatly assisted by the wealth of info here, thanks! I figured I'd share what's happened to my 2012 Cruze LTZ. 

Recently my wife (who normally drives the car) said she was getting an overheating/no AC on the instrument display. I found the water outlet neck on the driver's side was cracked. No big deal. I ordered an OEM replacement. I figured it was time for new plugs, belt, hoses, the works since it was close to 100k. I noticed during this maintenance that the water pump was leaking....ok, I added that to the list. I replaced the water pump only to have the thermostat housing blow up while sitting on the bench. That's right, it literally blew apart. There's some plastic tabs retaining the spring that holds the assembly together. A tab decided to let go and the spring went one way, the housing to the floor. Ok, order a thermostat housing... I replaced all of this and sent it out the door. 

This is when I was greeted with a CEL, the dreaded too lean code. Dadgum. No good deed goes unpunished right? I pulled it back in and sure enough I had a big massive air leak coming from the diaphragm on the valve cover. Then I noticed the bleed line going to the coolant recovery tank was leaking.... Really? Ok, ordered new valve cover and more hoses. In the mean time I made a replacement nipple that had cracked that the 5/16" coolant line to the recovery tank was hooked into. Now that'll never leak again. I ran the engine up to temp to leak check the system and no leaks. Good. But it started to smoke. Huh? Why are we smoking off the exhaust manifold? Must've spilled some coolant on it. It'll burn off. Yeah right! It got waaay worse and started stumbling. WTF? What's going on here? Did some research and looking around and the brand new plugs that have all of 15 minutes run time are soaked in oil. Huh? Where did this come from? I went to remove the PCV line from the turbo to the intake. SNAP.... Are you kidding me? Another item to go order, sweet.... It was damp, but not the source of a bunch of oil. Ok, let's pull the valve cover. Hmmm. Doesn't look bad. Did some more research and wondered why intake manifolds are showing up in my parts searches and commonly replaced items. Read on here about the check valve internal to the manifold. Yup, I looked and sure enough, no check valve. Great, now let's add another $300 item to the list. Will probably need to replace the cat now too due to the oil contamination. 

I'm not thrilled. This was a great running car. All I wanted to do was some good PM. I understand some parts fail. That's the whole reason for PM. Parts have been reasonably priced for what you're getting, but I shouldn't have to replace an entire valve cover, PCV line, intake manifold assembly, and possibly a cat due to a failed PCV check valve. This is beyond ridiculous. IF this is all I have to do, I'll have a bunch of new parts in this car. I don't have a warm fuzzy over the cheap brittle plastic parts used in the cooling system nor the crappy self-destructing PCV system.

I've already had the valve cover replaced at somewhere around 55k miles. How many times should this be replaced? It's not terribly expensive, but who replaces a valve cover as part of normal maintenance? 

Here's a few pics.

Home-made coolant return line nipple








Return nipple installed. I didn't have the right sized constant pressure clamp...








Doesn't look bad in here at all. 








I don't believe oil belongs in here....









Yup, no check valve inside the manifold.


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## dieselshadow (Nov 27, 2016)

*more pics*

I think I know where the oil came from...








Cleaned up and cleared the oil from the PCV port.








Another mess to clean up.








Yup, you can see the port for the PCV line that heads to the turbo and where the "umbrella" check valve is supposed to be. 








Oil was even coming out of the turbo wastegate linkage. I'm sure the cat is trashed. 








This doesn't look like your typical tune up does it?


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## AutumnCruzeRS (Sep 10, 2012)

Did something not seal correctly with the new cam cover? If I read your story right it seems that all your oil issues started after you installed the new cover.


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## dieselshadow (Nov 27, 2016)

No sir. Haven't received new cover yet. Still waiting on it, new intake, new heater hoses, (the one under the throttle body has been oiled and has gone soft) coolant recovery tank line, and new PCV air line. I had rigged up a temporary PCV air line with large bore heater hose just to get it running to get it out the door, but since it started dumping oil into the intake, there's no need for the temporary one.


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## cruze01 (Mar 25, 2011)

Am I missing something? A 2012 with less than 100K should still be under power train warranty. You should have taken in to the dealer, they would have covered the water pump, valve cover and maybe a few other things....


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## dieselshadow (Nov 27, 2016)

Yeah, only after finding out here did I know there was a 100k powertrain warranty. We bought an extended warranty to 75K, but completely forgot about the 100k. Plus in the beginning it was all about Preventative Maintenance, not full-on repair work. Ever since I pulled it into the garage a few weeks ago, it hasn't been road worthy enough to take it to a dealer.

I've been using OEM parts, so hopefully they'll honor the warranty. I'll be making a phone call tomorrow. I'm think the cat will need to be replaced due to oil contamination. Hopefully I won't have to pony up for that as well.


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## cruze01 (Mar 25, 2011)

Maybe you'll get lucky and GM will reimburse you for the parts. I know they have extended the warranty on the water pump and a few other problem areas to 10years/150K. Pretty nice of them to man up and take responsibility for items that they now are a problem.


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## dieselshadow (Nov 27, 2016)

Yeah, I hope so. I can't hold my breath though. I took this on and did the repairs myself. If they choose not to stand behind it, could you blame them? I am using OEM parts and can't drive the vehicle to the dealer, so maybe that'll count...


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## carbon02 (Feb 25, 2011)

You may wish to disconnect and drain the turbo intercooler lines to the throttle body. If there was that much oil in the throttle body intake, I have to believe there's a lot of oil in the turbo. 

Where did you find the fitting for the coolant line repair? Your the first one to come up with this clever alternative. It even has the ribs in the right spot for the retainer clip. 

If you got the AC off due to high temperature then this engine got pretty hot. I hope there's no head gasket problems. 

Thanks for the pics. Greatly appreciated for those of us that wiill have to do intake manifolds out of warranty. I agree the check valve seems to be a poor design, and I don't think Dorman or anyone else has yet to make an intake manifold replacement for this engine.

You may want to pressurize the coolant system for leaks at the head gasket, and look for combustion gasses in the coolant. 

I hope everything seals up well for you. I don't think we've ever seen oil out of the turbo like that.


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## weimerrj (Dec 4, 2011)

The water pump, neck, and PCV are covered under a 150Kmi special warranty for those parts.


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## carbon02 (Feb 25, 2011)

The water pump is covered for 10 years 150K miles, but I've owned my cruze since it's been new, and I don't remember an extended warranty coverage for the PCV valve. I believe it's covered by the 5 year/100K powertrain warranty. It also depends on when the car went into service. I bought my 2012 in late 2011. My 5 year powertrain warranty is over.


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## ChevyGuy (Dec 13, 2014)

With that much oil, I tend to worry about the health of the turbo.

I'd suggest changing the turbo's oil supply pipe. Later ones are insulated to prevent the heat from coking the oil and killing the oil supply.


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## dieselshadow (Nov 27, 2016)

The oil came from the PCV system, not the turbo. There was almost no oil in the intercooler line to the throttle body. The car wasn't driven when it failed. It was being run and heated up for post water pump and hose change coolant bleed and pressure check. I'm still waiting on parts to arrive to complete the repair. 

I made the fitting on my lathe. Had I had the right tooling, I could've have made it in less than an hour. But I made do with what I had. 

















































What sucks is I'll have to completely drain the cooling system again to replace the heater core hoses. The one under the TB is very soft due to oil contamination. 

Like I said before, no good deed goes unpunished.


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## ChevyGuy (Dec 13, 2014)

dieselshadow said:


> Like I said before, no good deed goes unpunished.


Hope you're at least making points with the wife.


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## dieselshadow (Nov 27, 2016)

ChevyGuy said:


> Hope you're at least making points with the wife.


Not really. When it rains, it pours. Now the Traverse won't get out of its own way. I'm so sick of breaking cars and working on them. 

It has no power, idles great, erratic RPMs, and the only code is Cat 2 is below efficiency threshold. I'm pretty sure it's the downstream O2 sensor that's bad causing the code. It holds a steady voltage while all the other vary as normal. Still doesn't explain the complete loss of power. Now my wife is down to driving my Colorado. Wonder what will happen to it?


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## jblackburn (Apr 14, 2012)

That is a LOT of oil.

I would flush the intercooler with soapy water and run a compression test when you get it all back together.

Traverses are known for plugged cats for no good reason. Quite common. You might have TWO cars that need one...


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## dieselshadow (Nov 27, 2016)

jblackburn said:


> That is a LOT of oil.
> 
> I would flush the intercooler with soapy water and run a compression test when you get it all back together.
> 
> Traverses are known for plugged cats for no good reason. Quite common. You might have TWO cars that need one...


Really? Good info right there. Thanks. I had no idea that was a common issue. No searches online about loss of power brought this up. 

Virtually none of this oil made its way through the turbo. It was all coming from the head passageways into the intake manifold. So the intercooler, turbo, piping, is all fairly clean. The engine only ran in the garage for about 15 minutes after the initial PCV failure. Blocking off the unmetered air leak at the valve cover causes the engine to suck the oil out of the PCV system into the intake manifold.


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## AutumnCruzeRS (Sep 10, 2012)

nice job on the lathe. I see a business op on that one. I bet you could do a group buy on those.


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## ChevyGuy (Dec 13, 2014)

jblackburn said:


> run a compression test when you get it all back together.


Probably not a bad idea. I don't know if 2012 was affected, but 2011 did have some problems with cracked pistons.


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## Steelmesh (Jan 16, 2016)

I am a bit lost in this thread, sorry:

What does the coolant return nipple (that OP lathed) have to do with the PCV valve?


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## obermd (Mar 3, 2012)

Steelmesh said:


> I am a bit lost in this thread, sorry:
> 
> What does the coolant return nipple (that OP lathed) have to do with the PCV valve?


If that nipple isn't there the PCV system will overpressure and cause the PCV valve to fail.


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## carbon02 (Feb 25, 2011)

The coolant return nipple is part of the cooling system, that the OP started working on. It's independent of the PCV valve.


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## dieselshadow (Nov 27, 2016)

carbon02 said:


> The coolant return nipple is part of the cooling system, that the OP started working on. It's independent of the PCV valve.


This. I was just working on PM replacing hoses, coolant, water pump, belt, plugs, when this nipple failed. It was during this repair that the PCV system had the massive failure.


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## gCruze14 (Mar 22, 2015)

dieselshadow said:


> Yeah, only after finding out here did I know there was a 100k powertrain warranty. We bought an extended warranty to 75K, but completely forgot about the 100k. Plus in the beginning it was all about Preventative Maintenance, not full-on repair work. Ever since I pulled it into the garage a few weeks ago, it hasn't been road worthy enough to take it to a dealer.
> 
> I've been using OEM parts, so hopefully they'll honor the warranty. I'll be making a phone call tomorrow. I'm think the cat will need to be replaced due to oil contamination. Hopefully I won't have to pony up for that as well.


U would think so.. but the exhaust system isn't part of the power train warranty.


Sent from my iPhone using Tapatalk


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## Gus_Mahn (Aug 16, 2011)

That line between the intake and turbo is so brittle. I've broken two. I can't imagine how brittle that'll be when these cars get some age.


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## dieselshadow (Nov 27, 2016)

How long are emissions components covered? I thought it was fairly long due to EPA regulations.


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## carbon02 (Feb 25, 2011)

dieselshadow- 

How did this turn out? Were you able to get it running?


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## dieselshadow (Nov 27, 2016)

Finally got the new valve cover in today. 

It has a new P/N than the previous one, but looks identical. 





































Old one on the bottom. 



















Car runs perfect, no CEL. Smoked really bad upon startup, but cleared out after about 1/2 hour run time. I'm going to let my wife use it tomorrow and check it over really good when she gets home. It has a bunch of new parts and fluids. 

Chevy told me to pack sand. They will only honor the warranty if I had brought it in. I had explained that it was in my garage for regular scheduled maintenance and I had used OEM parts. They said sorry.... I understand why they won't, but it doesn't remove much of the sting. I really like the car, my wife loves it, but I doubt I'll buy another car with so much plastic in the cooling system as this. Maintenance and repairs have been easy and relatively inexpensive, but a lot of this was totally unnecessary due to poor engineering specs and the over-use of brittle plastics used in areas where they shouldn't be. Everything is designed to be thrown away rather than maintained. I'm not an old man, but I value good maintenance and longevity rather than "throw it away" mentality. 

I hope Chevy reads this. I really like their products, but this makes it extremely hard to be loyal. I cannot afford to replace our car every few years. Even if I could, I refuse to. I shouldn't have to.


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## dieselshadow (Nov 27, 2016)

Car runs great. No CEL. 

Only problem is it leaks coolant. New thermostat housing is .030 smaller in diameter than the original one. The O-ring won't seal. So I get to drain the coolant once again and replace yet another **** part on this car. I'm so over this..... 

Have your laughs at this. The thermostat housing is the only part I bought that wasn't OEM. Go figure. My thinking was why buy the part that failed. Usually the aftermarket fixes these issues.


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## dieselshadow (Nov 27, 2016)

Well, here's a few pics showing the differences between the OEM and aftermarket thermostat housing. You can clearly see why it won't seal. The O-ring slides right over the new one without any resistance. It's a snug fit on the OEM housing. 



















Make sure to buy the OEM one.


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## carbon02 (Feb 25, 2011)

Looking at the Rockauto catalog, it appears that there are several manufacturers for the thermostat, and several manufacturers for the thermostat gasket as well. 

What is the manufacturer to stay away from? Does the new OEM thermostat come with a new gasket? I' guessing that the o-ring fit's in a groove on the water pump? So that there's no way that there could be two revisions of the gasket with different sizes?

You've done more work to this cruze in the past weeks than many of us have. Thank you for your posts, along with the pictures. I hope you get at least 100,000 miles out of this work. Hopefully it was just a fluke that everything happened at one time.


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## dieselshadow (Nov 27, 2016)

No problem. That's what forums are all about, right? The collective sharing of knowledge. 

I also bought this from RockAuto. It was labeled as Gates on my invoice, the box, and the site, but says MotoRad on the side. My bet is there is only maybe two places molding this piece and they change the name on the mold depending on the brand who ordered it. Dorman seems to be a name that has a lot of OEM plastic parts as well. I can't say they are from the same molds that AC Delco's supplier uses, but that's my suspicion. 

Here's the too small thermostat housing brand and part number.


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## carbon02 (Feb 25, 2011)

Wow- At close to $40-$50 for a thermostat hopefully RockAuto credits your account for this bad part. Typically they are pretty good at doing that, but it's the time to reorder it and have the car non drive-able that sucks. 

To anyone that reads this Rockauto has some under thermostat and some under thermostat housing categories. And I thought a $30 Oldsmobile Intrigue LX5 thermostat was expensive at $30. At least that was aluminum.


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## dieselshadow (Nov 27, 2016)

Yup. You darn skippy I'll be returning it. Hopefully I can fully convey as to why I am returning it so they don't pass on bum parts to unsuspecting folks. That's not their or the manufacturers intention, but it is what it is. It doesn't work. LOL


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## carbon02 (Feb 25, 2011)

I ordered a fuel pressure regulator on wholesale clearance that turned out to be the wrong one. They credited by account, and said throw away the part. Granted what I ordered was less than $20.

I just realized after my last post, that the connection we are talking about is the lower radiator hose connection, not the water pump gasket side. 

Since the lower hose has a new quick connection type fitting that I haven't worked with, I can see it leaking if the water pump connection size doesn't match the hose. 

Anyway glad things worked out for you.


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## dieselshadow (Nov 27, 2016)

It hasn't worked out just quite yet. If I can get this leak sorted out, the Cruze should be all set and ready for a bunch more miles.


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## carbon02 (Feb 25, 2011)

So I was googling how these new radiator hoses connect. Many of us being Gm owners haven't worked with them before. Apparently they have been common with German cars for years. Makes sense, since the Cruze was designed as an Opel in Europe, before going to Asia, and finally the US. 

Apparently the o-ring goes into the hose, then the metal band gets pushed down on the hose. The hose is then fit onto the corresponding part. In this case it's the thermostat. I think this means the O-ring in the groove inside the hose stays there, and the corresponding part seals on the cone edge. 

While I have not worked with these hoses before, maybe they could work with slight differences in diameter of parts like what the OP mentions above. 

Here's a video explaining the fittings and connecting them. I'd use Glycerin from the drug store on the o-ring vs. WD-40, but whatever works. 

https://youtu.be/91knYL1hEeU


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## dieselshadow (Nov 27, 2016)

New AC Delco thermostat housing installed tonight. It's the correct O.D. No leaks as of yet. Hopefully this nightmare has passed.


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## XtremeRevolution (Jan 19, 2012)

dieselshadow said:


> No problem. That's what forums are all about, right? The collective sharing of knowledge.
> 
> I also bought this from RockAuto. It was labeled as Gates on my invoice, the box, and the site, but says MotoRad on the side. My bet is there is only maybe two places molding this piece and they change the name on the mold depending on the brand who ordered it. Dorman seems to be a name that has a lot of OEM plastic parts as well. I can't say they are from the same molds that AC Delco's supplier uses, but that's my suspicion.
> 
> Here's the too small thermostat housing brand and part number.


I'll be replacing this as preventive maintenance soon and will likely purchase the Dorman part. I would guess that Dorman is a little more careful about fit and finish. 

Sent from my STV100-1 using Tapatalk


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## XtremeRevolution (Jan 19, 2012)

Correction...the Dorman part is for the thermostat housing. I don't plan to replace that. 

Looks like I'm getting the GM part. 

Sent from my STV100-1 using Tapatalk


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## dieselshadow (Nov 27, 2016)

Well after a quick check tonight, I'm not super pleased to report that joint was wet, not dripping, but wet. I topped off the coolant tank, cleaned up the evidence, and will check again tomorrow. I'm hoping that after a few heat cycles it'll settle in to its new home and be dry.


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## Spyder918 (Apr 13, 2016)

Sorry, you had did so much trouble but great write-up. Thanks.


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## XtremeRevolution (Jan 19, 2012)

This issue is well-documented in this thread, and other threads linked inside it:

http://www.cruzetalk.com/forum/34-g...4-pcv-valve-cover-intake-manifold-issues.html


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## GSTboy (May 10, 2018)

I'm getting large amounts of oil into my intake system again and I'm not sure where to start. I've done the check valve fix, installed a catch can, and replaced the valve cover. But my car is burning oil and my catch can is filling up. And reccomendations on where to look?


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