# Blow by, please help



## Thebigzeus (Dec 2, 2018)

2011-2016 Cruze 1.4 PCV Valve Cover/Intake Manifold Issues


2011-2016 Cruze 1.4L PCV Valve Cover/Intake Manifold Issues Video: I made a video to help better explain how this whole PCV system works to supplement this article. Overview I find myself having to explain this issue to someone almost daily, so in the interest of brevity, I'm creating a...




www.cruzetalk.com





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## JLL (Sep 12, 2017)

Jarret said:


> My Cruze has developed blow by recently after a really bad misfire caused by a bad coil, it now has some pretty good blow by when you take the oil cap off and begins idling weird when taken off, could someone please help me u d’état and what is causing it and how severe it might be? Thank you!!!


Besides what @Thebigzeus said, I'm a little confused by what you mean. By design the LUJ is uniquely designed to have a very small vacuum in the crankcase with the engine idling. By removing the oil cap or dipstick with the engine running you are letting unmetered into the engine, so it's going to idle weird.


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## Mr_Pat (Mar 7, 2021)

Dont remove the oil fill cap or the dipstick when the car is idling ,, or you essentially cause a vacuum leak Not sure how you determined this as blowby.. now if you drive your car and its blowing the dipstick out of its tube you have blowby....


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## Jarret (Feb 4, 2021)

JLL said:


> Besides what @Thebigzeus said, I'm a little confused by what you mean. By design the LUJ is uniquely designed to have a very small vacuum in the crankcase with the engine idling. By removing the oil cap or dipstick with the engine running you are letting unmetered into the engine, so it's going to idle weird.


But is it supposed to be pressurized? No right? It should have vacuum and my car blows air out of the oil filler when you take the cap off, which isn’t supposed to happen right?


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## snowwy66 (Nov 5, 2017)

If you don't see smoke then you don't have
blowby.

Blowby comes from worn piston rings. And looks like smoke. And can't be fixed without tearing the engine down.


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## Mr_Pat (Mar 7, 2021)

Check your pcv make sure it's not clogged up make sure the check valve at the turbo isn't clogged or stuck closed as well..


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## Shroomie (Jan 16, 2017)

if the pcv is not clogged.. use a top end cleaner and unstick your rings.


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## snowwy66 (Nov 5, 2017)

If the rings were stuck. Wouldn't they break?


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## JLL (Sep 12, 2017)

snowwy66 said:


> If the rings were stuck. Wouldn't they break?


Yes but, not necessarily catastrophicly. It would put a lot of additional stress on the ring lands though.


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## Shroomie (Jan 16, 2017)

snowwy66 said:


> If the rings were stuck. Wouldn't they break?


mine were stuck and didn't break. I don't know how long or anything. I just know when I pulled the head I could move the piston in the bore a smidge and no signs of rings lol... then I soaked it in oil and they appeared and couldn't move the piston like before


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## Jarret (Feb 4, 2021)

snowwy66 said:


> If you don't see smoke then you don't have
> blowby.
> 
> Blowby comes from worn piston rings. And looks like smoke. And can't be fixed without tearing the engine down.


Well there definitely isn’t any smoke lol, is it a pcv thing?


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## JLL (Sep 12, 2017)

Jarret said:


> Well there definitely isn’t any smoke lol, is it a pcv thing?


Let me try to get this straight.....

The only thing that makes you think you have a problem is that you feel air/oil coming out of the oil fill hole when the oil cap is off and the engine is running. Is that correct?


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