Chevrolet Cruze Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 · (Edited)
Thanks for the great threads on PCV system details. It's helped me work through another possible cause of my ongoing issues, but I am not 100% certain that it's actually faulty.
I don't have smoke from the exhaust. I do still have lumpy idling.
The diaphragm isn't whistling and I believe I can see the orange nipple through the inlet manifold, which seems to suggest that it's where it should be.
I pulled the corrugated pipe off the inlet manifold whilst the engine is idling and it is drawing a vacuum, which feels like the opposite of what it is supposed to do??
And there is an obvious pressure up through the dipstick when I pull it out...

Really hoping to find a quick fix now.

I had loads of oil in the bottom boost pipe (to the intercooler), which i have cleared out.

I don't have any fault codes on the Op-Comm diagnostics.

Any suggestions are greatly appreciated.

****Edited to add****.... Just applied my thumb over the diaphragm vent and it started making a whistling noise, felt as though it was drawing air in. With thumb over the diaphragm vent there was a drop in the pressure from the dipstick pipe.

Sounding like a standard diaphragm failure???
 

·
Registered
Joined
·
325 Posts
To me yes, sounds like the failure of the valve cover/burst disc/diaphragm assembly.

Are you sure the orange nipple is still intact?
 

·
Registered
Joined
·
8 Posts
The way the pcv system is set up on these engines is a very poor example of the GM engineers. It is my own belief but I believe that if you change the pcv system to a positive vacuum and get away from that sorry excuse for a valve most of the running problems for the 1.4 turbo would disappear.
 

·
Administrator
Joined
·
15,750 Posts
Yes, your vacuum regulator diaphragm has ruptured and your valve cover needs to be replaced ASAP. That is absolutely the source of your problem.

Furthermore, vacuum is NORMAL in the PCV system. Under idle, it is supposed to have vacuum, at -6 PSI or more downstream of the pressure regulator diaphragm, and between 11 and 18 inches of water upstream of the pressure regulator diaphragm.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #5 ·
Thanks. Replaced the cover. Still no real joy. Rough idling continues... sounds like it's chugging like a tractor. Fine at higher revs, but still feels like its lacking power or maybe no boost.
Very frustrating...
 

·
Registered
Joined
·
665 Posts
This valve is a joke... I just finished the "bypass" for my 3rd car this week. The failure happened randomly, 66k on the first car, 44k on the 2nd and 81k on the one I just fixed. When you replace the cover be careful, I always used a gasket maker for 2 areas of the engine that have a small gap. Also make sure the gasket seal stays in place. When I replaced the cover first time the seal went inside to the spinning parts close to the timing chain and got damaged, I had to use the original seal instead. However the design is cheap, they could do a better job....
See the original valve in my attachment, I was able to find it into the manifold :)
 

Attachments

1 - 6 of 6 Posts
Top