# 2013 1.4t LT Engine Chirping Sound, Please Help



## carbon02 (Feb 25, 2011)

Check the PCV Valve in the valve cover. Google it on this site. Essentially remove the ecotec cover from the top of the valve cover, and check the valve cover for air being sucked in at the check valve. 

There's a whole very large thread dedicated to the PCV Valve/Valve cover replacement, and the replacement check valve in the intake manifold that causes the PCV failure.


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## caughron01 (Mar 25, 2013)

carbon02 said:


> Check the PCV Valve in the valve cover. Google it on this site. Essentially remove the ecotec cover from the top of the valve cover, and check the valve cover for air being sucked in at the check valve.
> 
> There's a whole very large thread dedicated to the PCV Valve/Valve cover replacement, and the replacement check valve in the intake manifold that causes the PCV failure.


This should be covered under my powertrain then right? Thanks for the info I really appreciate it!


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## Robby (Mar 1, 2013)

Remove dipstick while idleing....any difference? If noise is gone, needs a crankshaft seal (belt side...powertrain).

Noise doesn't change? Check for a loose spark plug (wait till engine is at ambient temperature.)

Rob


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## caughron01 (Mar 25, 2013)

Robby said:


> Remove dipstick while idleing....any difference? If noise is gone, needs a crankshaft seal (belt side...powertrain).
> 
> Noise doesn't change? Check for a loose spark plug (wait till engine is at ambient temperature.)
> 
> Rob



Removing the dipstick didn't change too much of anything that I really noticed, it did start chirping again for a second once I put the dipstick back in. 







I will check the spark plugs once it cools down. I just got back driving home from work so its still pretty hot.

I also did not notice any vacuum from the little circle piece on the right side, is that normal?


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## Robby (Mar 1, 2013)

A good burst valve will have no vacuum leaking at the small port.

Rob


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## dhpnet (Mar 2, 2014)

That's the exact sound a loose spark plug will make.


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## ChevyGuy (Dec 13, 2014)

Robby said:


> Remove dipstick while idleing....any difference? If noise is gone, needs a crankshaft seal (belt side...powertrain).
> 
> Noise doesn't change? Check for a loose spark plug (wait till engine is at ambient temperature.)


Agreed. But I thought a PCV valve failure in the manifold could cause excessive vacuum in the crankcase leading to a squeaking seal. Eventually, that bad valve will cause the PCV in the valve cover to rupture leading to other problems.


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## Robby (Mar 1, 2013)

ChevyGuy said:


> Agreed. But I thought a PCV valve failure in the manifold could cause excessive vacuum in the crankcase leading to a squeaking seal. Eventually, that bad valve will cause the PCV in the valve cover to rupture leading to other problems.


When the check valve fails the excessive vacuum in the crankcase is vented through the blow by hose from crankcase to airbox.
Over time though, since this vent is supposed to bleed off positive crankcase pressure (occurs because PCV shuts off with deep throttle/low vacuum operation), but is bleeding negative vacuum because the check valve isn't, it is overwhelmed. Eventually, the burst valve (what we keep calling the pcv) diaphragm ruptures due to excessive pressure.
This creates a giant vacuum leak at idle with resultant codes and poor operation.

Rob


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## caughron01 (Mar 25, 2013)

Well I appreciate all of the help guys! I went out to check my plugs and one of them was a bit loose, I could loosen it with just the socket and extension bar by hand without the socket wrench. I tightened it up and so far the noise has disappeared. I will find out tomorrow if this has for sure fixed it when I drive to work. Thanks again for everything, I knew I could count on this Awesome community of Cruzers! You all Rock!!


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## NebraskaCruze (Dec 11, 2017)

I haven't been able to locate the thread that goes in to the PCV that you talked about above. My 2013 Cruze LT has started making a chirping sound whenever I accelerate similar to this noise and dealership said it needs a new intake as well as a new valve cover. It's just started making this sound in the last couple of weeks- is this something that could cause failure at any time?


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## Robby (Mar 1, 2013)

Start by checking for a loose plug(s).

How did the dealer make the manifold and cover diagnosis?

Rob

BTW: are you certain you are beyond the 5yr/100k powertrain warranty? The parts you mention are covered if they have failed.

Rob


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