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Discussion Starter · #1 ·
Hi all , I installed my second valve cover today and my car (2012) still had a rough idle . Thanks to this forum I decided to dig a little deeper and removed the intake manifold and found the check valve missing . I hope this is the reason that the engine still ran rough after the valve cover change ?

Can somebody give me the torque values for the intake manifold ? and the torque sequence ?

Thanks , Dave

20160410_135146-1.jpg
 

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My check valve has been "missing" for probably tens of thousands of miles, and I do not have a rough idle. I am doubtful that your rough idle is because of the check valve.

Have you double checked the spark plug springs to make sure they are straight and the boots for tears?
 

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Discussion Starter · #3 ·
Plugs are new , boots are good and the springs look good . I ordered a new Manifold . What else would cause the rough idle ? I never checked the codes because the symptoms were identical to the first time it happened and the PCV was sucking air . 122,000 miles and always had some oil in the throttle body but the car ran and idled fine .
 

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Plugs are new , boots are good and the springs look good . I ordered a new Manifold . What else would cause the rough idle ? I never checked the codes because the symptoms were identical to the first time it happened and the PCV was sucking air . 122,000 miles and always had some oil in the throttle body but the car ran and idled fine .
Good question, I don't know. Are there still codes present? It would be good to know what they are.

In your case, it makes sense to go ahead and replace the manifold, and see what that does.

In my case, it didn't make sense to replace an expensive part since my Cruze runs fine, when I am almost ready to buy a new Cruze in a matter of months.
 

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Mine ran ok with the check valve missing. There was the occasional poof of blue smoke and oil at the throttle body, but it ran ok once the valve cover was replaced.
 

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Discussion Starter · #6 ·
I disconnected the battery and lost the codes .
The new manifold should arrive Thursday , Ill post my results.
Thanks for the reply's
 

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If I remember correctly I think I torqued mine to 79 in-lbs but don't remember the sequence. I believe XtremeRevolution did a super duper write up on this a few years back which you should be able to search for.
 

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I believe the write up was for the valve cover. I don't think we have a write up anywhere for the intake manifold.

I'd be interested to see what the inside of the intake around the check valve looks like. Does the check valve get consumed in the engine, or is it stuck in the intake, and is there hope for cleaning and reinstalling it vs. buying the entire $300 intake manifold.

The 6 intake manifold bolts get tightened to 15 ft/lbs.. Not a lot of torque. Intake.JPG
Intake 2.JPG
 

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Discussion Starter · #10 · (Edited)
I believe the write up was for the valve cover. I don't think we have a write up anywhere for the intake manifold.

I'd be interested to see what the inside of the intake around the check valve looks like. Does the check valve get consumed in the engine, or is it stuck in the intake, and is there hope for cleaning and reinstalling it vs. buying the entire $300 intake manifold.




The 6 intake manifold bolts get tightened to 15 ft/lbs.. Not a lot of torque. View attachment 189314
View attachment 189322
It was my intention to unstick or fix the check valve but it was missing . See pic from the original post . I got the new Manifold for 230.00 delivered and the valve cover for 51.00 delivered , I've never spent any money on this car other than routine maintenance ( and the first 50.00 valve cover) so I figured Id give it a try .

Thanks for the help and Ill post my results (prob not until after the weekend though)
 

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I decided to dig a little deeper and removed the intake manifold and found the check valve missing . I hope this is the reason that the engine still ran rough after the valve cover change ?
IIRC, the missing check valve causes the new valve PCV valve to fail prematurely. (over-stresses them) But until that happens, it won't cause poor idle.
 

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Discussion Starter · #12 · (Edited)
I installed the intake manifold and the car runs fine now , it actually idles better than it did after I installed the first valve cover . After the first cover the idle seemed slightly rough but not bad enough to check further. After you crack the code for the 7 or 8 different types of connectors to unplug hoses and harnesses:uhh: the total job took about 4 hrs . One added benefit was an increase in MPG , it went from high 36's to 39 on my daily commute. 20160419_162236_resized.jpg Thanks for all the help guys .

Dave
 

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Thanks for the update.

I wonder why yours ran rough, when other didn't, after the check valve goes MIA. Perhaps it depends on whether the check valve is just stuck, vs. being completely missing?

I installed the intake manifold and the car runs fine now , it actually idles better than it did after I installed the first valve cover . After the first cover the idle seemed slightly rough but not bad enough to check further. After you crack the code for the 7 or 8 different types of connectors to unplug hoses and harnesses:uhh: the total job took about 4 hrs . One added benefit was an increase in MPG , it went from high 36's to 39 on my daily commute. View attachment 190882 Thanks for all the help guys .

Dave
 

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It was my intention to unstick or fix the check valve but it was missing . See pic from the original post . I got the new Manifold for 230.00 delivered and the valve cover for 51.00 delivered , I've never spent any money on this car other than routine maintenance ( and the first 50.00 valve cover) so I figured Id give it a try .

Thanks for the help and Ill post my results (prob not until after the weekend though)

Where did you find the Intake delivered for $230? That seems like a pretty good price, did you take a chance on "e bay". This was a complete manifold, or did you transfer the parts. like the fuel injectors and the mass air flow sensor?
 

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Discussion Starter · #15 ·
Where did you find the Intake delivered for $230? That seems like a pretty good price, did you take a chance on "e bay". This was a complete manifold, or did you transfer the parts. like the fuel injectors and the mass air flow sensor?
This was a new complete manifold with injectors , throttle body all sensors and gasket . I asked if it was ever installed or had any parts removed or replaced and the answer was no . He had good feedback and return shipping would probably be about $ 10.00 so I took the chance and it paid off. Shipping was fast too.

12' 14'Chevy Cruze Sonic Trax GM 55581014 ACDelco 55581014 Intake Manifold | eBay

Dave
 
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