1.4T PCV repair - an alternative

[efaily]

Negative on the Dorman kit. The intake manifold has the same restrictions in the runners as the stock manifold. I bought it from Amazon for $187.78. I'm sure there are cheaper ways to bypass the stock PCV system, but this kit seems to address the issues with the stock parts, and makes the valve cover diaphragm serviceable just in case. Plus, it gives me the chance to port the intake before I install it.

 

[zomby woof]

How does it make the valve cover diaphragm serviceable? Not seeing it.

 

[efaily]

The hard plastic cap over the rubber diaphragm on the valve cover is removable on the Dorman valve cover. It's not with the GM valve cover, so you can't replace the torn rubber diaphragm separately.

 

[zomby woof]

I'm sure there are cheaper ways to bypass the stock PCV system, but this kit seems to address the issues with the stock parts, and makes the valve cover diaphragm serviceable just in case. Plus, it gives me the chance to port the intake before I install it.

It looked like you were talking about the ZZP kit.

I've tried to think about a way of eliminating that diaphragm because it will fail. I'm thinking some sort of check valve with a restrictor in it, but it's hard to package in there

 

[efaily]

Sorry, nope. I was referring to the Dorman intake manifold/valve cover kit. The Dorman valve cover kit has a removable plastic cap over the rubber PCV diaphragm in the valve cover, so the diaphragm itself is serviceable without replacing the entire valve cover. Hopefully that won't be an issue because their intake manifold incorporates a retainer behind the check valve to prevent it from ever coming loose and being inhaled by the engine into a combustion chamber. The design seems sound to me, so hopefully they will last far longer than the stock GM parts.

 

[zomby woof]

Nothing short of a metal check ball/valve will last. The retainer is a nice touch but it's not coming out because it doesn't have a retainer. It's coming out because the rubber is failing. The retainer won't stop the rubber from failing. Even the silicone diaphragm in the valve cover is failing and it's in a much nicer environment than the one in the intake.

I used to service heavy mechanical presses that had a very similar diaphragm but in a much cleaner, cooler environment. They had a 100% failure rate. It was just a matter of time.

 

[efaily]

Yep, I understand almost nothing lasts forever. I also understand that manufacturers have to engineer things to a certain price point, which Chevy obviously did. The part that's harder to understand is that Chevy obviously knew their design was a very common point of failure, but never bothered to revise it. I bought these Sonics for my kids to get them through high school & college. I don't need or expect the Dorman parts, or other Chevy parts for that matter, to last forever. I do think the Dorman parts will last for more than enough years for my families needs, not to mention if and when they do fail, not cause additional issues and be easier to repair.

 

[Thrasher2019RS]

IANAL, so pardon the legal question... But is there not a class action that could be brought to bear against Chevy?
I mean this isn't just prolific, it's 100% an issue across the models, and causes serious issues.

Thanks, T

 

[Ffor]

Did this couple years ago been working great! But yesterday running down the freeway I noticed the smell of oil and saw smoke. Pulled over and under the hood was covered in oil. Looks like its blowing out somewhere at the top of the engine. Noticed the diaphragm was sucking air at idle. Changed oil and cleaned the two aftermarket pcvs and drove it today and after a while of driving it did it again. What do I look for now? Could it push oil out of that diaphragm?

 

[Ffor]

Anyone ever plug the diaphragm in the valve cover?

 

[zomby woof]

Yes. Do it just with your thumb while it's running and you'll hear the front main seal start chirping.
When our blew and I was waiting for a new valve cover I put a restrictor in the opening, a mikuni main jet, if I recall, about a 1mm hole. If you don't restrict it you'll set a lean code.

I think if it goes again I'm going to plug it and instead install a check valve with the restrictor, such that when there's no vacuum, or boost, the check closes to not let anything out

 

[macdiesel]

Still going strong two years later!

I've since added a cheap ebay check valve. Just as a matter of maintenence, I bought two new PCV valves (2016 Kia 1.6T) off rock auto to replace the old junkyard ones I initially used and both leaked - and I even paid for the better ones, so I put the junkyard valves back in and added the check valve for safety.
I also made up a little kit for a friend who wanted to do the mod to his Cruze. I'll post a pic if I can find it.

So just a warning, if you're going to do this mod, check the PCV valves and make sure they don't leak or you'll be chasing your tail!

What kind of mileage have you put on the sonic since installing your kit? Might be looking at your instructions when I supplement the dorman manifold I added last year.

 

[zomby woof]

I said on the last page two years, it's actually been three, since December 18.

We've put on a little more than 60,000km since I first installed it

 

[macdiesel]

Has anyone actually used the Dorman manifold & valve cover to fix this issue? The Dorman valve cover appears to make the PCV diaphragm serviceable, unlike the stock valve cover. The Dorman intake looks like it may not include the flaps to restrict airflow, but I'm not sure based on the pictures I've seen. I'm wondering if anyone knows for certain?

I’m not sure the Dorman valve cover is serviceable. According to Dormans reply in their informational YouTube video. Do you have a different manifold?

Initially, when I looked into the manifold I came across their product video and it appeared the pcv diaphragm would be until I scrolled through comments.

 

[efaily]

Nope, I have the Dorman kit with intake manifold, valve cover, and hose for both Sonics. I thought it was serviceable because of the video. False advertising! I want my money back! LOL

 

[rickguyface]

Hello!

I recently did this and I can't seem to track down the chirping coming from my engine. I've traced every line I put in and they're all clamped down tight around the barbs. I don't think the PCV/check valve I'm using leak, I've blown through em and it just makes my mouth taste like oil fumes, but without fail the car just wants to be heard. The Epoxy around the nipple in the valve cover is on solid too, no visible leaks or holes where a leak could come through.

I've got one more cover, what can I do to prevent this issue?

 

[zomby woof]

The chirping is usually the front main seal sucking in air because the vent in the valve cover is not working correctly

 

[LOAS]

I'm new to this problem. this is probably a dumb question but why can't you use the factory port for the PCV instead of blocking it off? I know about the factory check valve in the intake failing so doesn't it work like a vacuum port then? I figured out my own question. I didn't realize it was fed from a port in the head and through the valve cover. Can the port that goes from the intake to the inlet side of the turbo be used?

 

[83Daytona]

Old Thread but I wanted to chime in to see if folks are still using this method. I can no longer find any other posts/threads on this method.

I am considering this method but wanted to explore this idea:
(A) Block the rear passage between the Valve cover and the head (dealers choice to block the head passage or the valve cover passage)
(B) Drill into the valve cover and vent directly to atmosphere / catch can (plan to use a check valve but wondering is this even necessary? See thought #1 below) (I am also considering venting through the oil cap)
(C) Plug the PCV hose going to the Turbo Inlet. (see thought #2 below)

A few thing things with this method I wanted to get opinions on,
(1) This method will yield no vacuum sucking out the PCV gases - however, is this necessary? Old cars vented right to atmosphere through the valve cover.
(2) with the PCV blocked off at the head, The return hose to the turbo would only be sucking intake air, not intake plus PCV gasses, so it seems like a wasteful return after blocking PCV, why keep it around? (EDIT: After thinking about this, this would only happen if the non-return valve is damaged or missing causing intake air to leak into the PCV plenum. If all is intact, the non-return valve will be closed under boost and the PCV passage is closed off due to (A) above. So no real reason worry about blocking this passage off if all check valves are working - Even if the non-return valve is gone, its still probably not the end of the world - Just wasteful to recirc intake air back into the turbo.)
(3) Does the condition of the non-return valve in the intake (orange nipple in intake) matter with this mod? Is there any effect on the Vacuum bladder used as a reference input "signal" to trigger the BPV solenoid? (I would think not as the intake is still going to see vacuum or boost regardless of if the crank case is exposed / breathing into the intake / turbo)


(Edit to add: This topic led me to thinking about my 7.3 powerstroke. A lot of folks like to vent that system overboard however, the downside of this is oil fumes and drips on the ground which could be the same situation with the Sonic. However, the 7.3 routes the CCV (they call it CCV) directly into the intake tube which can cause some oil build up in the charge air cooler, however there is no concrete evidence this causes a mechanical issue. I may explore routing the Sonic PCV directly into the intake plumbing rather than the intake manifold. There will always be airflow / suction in the intake so long as the engine is running.)

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Update 12/27/2024
I have completed my PCV reroute to the air box. I used a new doorman valve cover and plugged up the lower portion of the PCV port with a rubber stopper and black RTV. I then drilled a hole in the top of the valve cover above the PCV passage and fitted a 1/4 MIP brass fitting that converted up to 3/8” barbed. I ran 3/8” line over to the bottom of the air box. I then cut the currogated PCV return line to the turbo and plugged both ends with a rubber cap and some black RTV. Waiting Over night for all of the RTV to dry but will test it out tomorrow And report back.
I would like a better outlet fitting at the valve cover, but this one should work for now. It was what i could find off the shelf at Home Depot.
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Update 12/28/2024
Drove around the car today - In town Mostly 50mph or less. So far so great. Car has never idled so well (NOTE: I did replace spark plugs and reconnect a dangling vacuum line so not all of the smooth running can be attributed to this PCV repair). The real question is I have finally cleared the CEL after years of ignoring it due to the PCV system. We will see how long this lasts. by using the clear vinyl tubing I can keep an eye on the build up or PCV gases, I could tell it was working because after my first 15 minute drive I had condensation build up in there, which is a good sign it was working. Time will tell - So far so good - No strange noises or leaks etc.
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Update 1/13/2025
PCV re-route seems to still be doing well - I can see a gold hue starting to build up in the clear vinyl hose going to airbox - so its definitely working / routing gasses & oily mist. The new valve cover has a slight leak at one of the front bolts, I am going to try tightening it up & adding some black RTV around the bolt stem/head. For the first week it *seemed* like I cleared up the oil leak / burning oil smell form the car with this fix up, that being said I do have the leak I just mentioned above to take care of which I think has contributed to some burning oil smell that has returned after about 1.5 -2 weeks.
I've also looked into the ZZP kit, They add a vent to the oil cap and I am not sure why?
I do want to share an amazing link / write up I found regarding PCV systems. Its from a Nissan forum but its the most comprehensive write up I have seen including methods to re-route & modify the system. Lots of relevance to our engines: https://www.sr20-forum.com/informat...ly-explained-naturally-aspirated-edition.html