[JayTee2014]

Too much to read.. .

Was the vehicle bought new or used? Going too long between oil changes will also start to plug up the PCV valve. In very cold weather and short drives, water vapor builds up in the crankcase oil. Combine that with dirty oil and the small PCV orifice can get plugged from frozen moisture in the valve cover where the PCV orifice is located. Also, GM is not the only car maker to have this issue.

My fix... . buy a new oil cap, drill a hole into it, and mount a pressure relief valve which will release crankcase pressure if the PCV ever does freeze in cold weather.

 

[JayTee2014]

It could save a lot of people many headaches! All it takes is an idea and I think you have a great one!

Well, maybe. It is just an idea. I don't have a 2.4L to experiment with. If I can get a used oil cap for my 3.6L V6 I might try it on there just to make sure that having a pressure relief valve won't set any codes. And only should need something like that for winter use.

 

[JayTee2014]

Just as an aside. . .

Many do not understand how much moisture can build up in the crankcase especially in winter months. I have an Oil Catch Can on my 2015 Equinox 3.6L which has an external PCV orifice. So easy to install the catch can.

It is primarily installed to collect oil and combustion vapors and reduce the amount passed through the intake manifold and build up deposits on the back sides of valves. I will collect maybe 3 or 4 ounces of black liquid every 1,500 to 2,000 miles in warm weather (+45F).

But. .. in winter months, the can will fill (8 ounces) in as little as 2 months or 1,500 to 2,000 miles. But the contents are mostly a yellowish water/oil emmulison. This is the result of cold starts and short drives. If you notice, in winter, the exhaust coming out the tail pipe is steamy most of the time. Well, much of that also gets passed into the crankcase as well and never gets heated enough to burn off.

Below is a picture of just some of the collection in winter 2015 and the second. . . . summer after some 3,000 miles or so.

Summer Oil Can Collection - - - -

 

[JayTee2014]

Interesting that there has been no chronic PCV issues reported on the 3.6L LFX engine. There was also a change on that engines PCV orifice, though, for a similar issue. The holes were a bit undersized in the orifice so the 2014/15(?) onward had larger sized openings.

In the new 3.6L LGX/LGZ engines, the PCV is again, all internal. However, it uses larger diameter tubing and most all sits well inside the engine valley where temperatures are much higher with little or no chance of moisture collecting and freezing.

You can all thank the EPA for this since they mandated no venting of crankcase vapors.

My 2 cent view on this is that it's all stop gap measures to try and make up for the gross damage to air quality and the ozone layer caused by the "City In The Air". . .. continuous 24/7 air traffic at high altitudes. After all, GE, Intel, Microsoft, TI, Samsung, World Bank/Financial Guru personnel, etc all have to have their imported engineering/professional staffs flown in and out from the mid east and Asia constantly.

Big Business created this issue and it always falls on the general public and consumers to pay the price. The price shows up in many different ways even in something such as this PCV issue.

 

[JayTee2014]

I recall a GM rep a few years ago on this site. Seems like this PCV issue getting worse.

It got "worse" this year because so many parts of the U.S. have gotten days and weeks much colder weather than usual. Ergo. . .. frozen things.

 

[JayTee2014]

I know this does not happen , but why wouldn't the dipstick pop up with the pressure in the crankcase instead of blowing the seal. You would certainly think that the little O rings on the dipstick would blow before the main seal.

I thought that also, but apparently the tube for the dip stick goes into the oil sump below the oil level line. So no air pressure can travel up the tube. Oil does not compress since it is a liquid. Therefore, the main seal gets the pressure since abut half of it is above normal oil level when the engine is running and oil is circulating.
Someone posted a picture here recently of the rear seal "blown" out. In reality, only the upper quarter or so of the seal was affected and it did not really blow completely out. The oil seal has a lip and an edge that normally pushes inward toward the engine crankcase. When the seal blows, that inward facing lip gets pushed outward and then no longer has enough sealing ability, so it allows oil to flow outward along with the pressure of blowby gases.

 

[JayTee2014]

What is most absurd is - - -


JTrexel1
Newbie

Join Date: Feb 2019
Posts: 1

 

[JayTee2014]

Get ready .. soon as single digit or lower temps start up this winter. . .. .



There'll be more new posters with blown 2.4L main seals.


Get a vented Delco FC219 oil filler cap and keep it cleaned in very cold weather.

 

[JayTee2014]

Thanks for the very good write up and detective work. I Pretty much agree with your conclusions.

And, in the case of the GM 2.4L engine, even the "clean side" isn't relieving the pulsations by allowing enough (any?) air to flow into the intake via the throttle body which is kind of surprising.
Without knowing exactly what the entire clean side air flow path might be from the crankcase to the valve cover where the clean side allows/vents PCV vapors, and without knowing exactly what the PCV flow path is for the internal PCV orifice . . . this all seems interesting and points out that the system does not function as well as it should. As we all know.

I'm thinking even when the PCV orifice is not clogged, it's size and possibly other path restrictions, do not function well enough to allow all air flow completely.



On a related note . . I also have tried a vented cap (and also the FC219) on our 2017 1.8L four banger Sonic engine. It also, exhibits some air pulsations when a vented oil filler cap is used, but not as pronounced as you described. I have as yet, connected my OBD II scanner to the Sonic to see what pressures are at idle for intake.

I can say, I don't notice any clicking of bouncing of the check valve in the other vented filler cap I purchased. It originally did not have a ball, but I found a 1/4" ball that fit and does the trick. But it essentially stays in place during idle. . . . or moves so little that I notice no sound.


Before selling our 2015 Equinox 3.6L V6, I also checked and found that if i installed a vented filler cap, it remained closed as you also found.

So that 3.6L V6 apparently has a properly designed PCV path and also provides enough vacuum even at idle unlke the 2.4L engine.



The bottom line seems to be that the 2.4L PCV path fails to provide sufficient flow of PCV vapors and a vented oil filler cap would be a wise addition to provide pressure release at idle as well as while driving should the internal PCV orifice freeze or clog with carbon and combustion debris.

Jaytee,

Tell me if my logic is correct... I have a question for you.
==>I don't think the 4 cylinder LEA equinox engine ever has crankcase vacuum at idle...<==

Here is my logic.
As you know I have the cfm vented oil cap.... which will, relieve crankcase pressure, but will not let air into crankcase.

My 2016 has 18k miles
The other 2016 has 34 k miles
My 2013 has about 38 k miles
All well maintained.
Low Temperature last night was about 25 degrees, this morning at cold start time 35 degrees, and it warmed up to 45 degrees when I took cars out for a drive, a clear and sunny day. Two equinox's are garage kept, garage is about 10 degrees warmer then outside temperature.

I did a quick "deep dive" , investigation, ... on cfm oil cap and its relation to crankcase pressure or crankcase vacuum / intake manifold vacuum ....here is a simplified explanation....

When I cold started my 4 cylinder equinox's,
The vented oil cap bounces up and down as it lets crankcase pressure escape from crankcase.
My fuel trims are close to zero on both long and short term, which is perfect.

Scan tool, tells me intake manifold VACUUM is about 8 psi....at idle, at Start up, which is normal.
( 8psi vacuum = minus 8 psi)
Thus theoretically, ~~>since the intake manifold is pulling a strong 8psi vacuum, it should be sucking much crankcase fumes through the dirty side PCV , and thus putting crankcase in a vacuum <~~p

After 5 minutes of idling, still no change, I still have the ball in the vented cfm oil cap bouncing up and down relieving crankcase pressure.
I pull off the decorative plastic filter cover off cfm oil cap and I feel air blowing out. Like lots of little puffs of air.

Here is my guesss...
I am not sure, ....but perhaps the "noise" comes from the nylon ball hitting the top of the cfm oil cap , "aluminum housing stop" as the crankcase gas pushes the ball up,
and then after hitting the aluminum housing top, it bounces down along with gravity. Then, as the nylon "ckeck valve" ball gets close to "sealing" the crankcase, the air escaping from crankcase pushes the ball upward and out of the way again.... hence the pulsing of air out of engine.

If I put my hand flat on cfm oil cap, I can stop the air from exiting crankcase via oil cap,
Thus no air comes out and nylon check valve ball ball stops bouncing, it is silent. Take my hand off, and nylon ball bounces up and down again...
^^^^ that is cold start ^^^ and 5 minute warm up on all three 4 cylinder equinox's.
NEXT,
Then I take the equinox out for a 50 minute drive around town, stoplights, top speed 45 mph, and sun is out it is 50 degrees outside. Come home let car idle for a few Minutes and pop open hood, remove the decorative cfm oil filter cap,
And air is still blowing out of crankcase through cfm oil cap
And
Intake manifold has a vacuum of 8 psi per scan tool.(perfect)

Repeat ^^ with other 2016 Equinox, same results.

My Conclusion... is that the crankcase never sees a vacuum
Even though intake manifold is pulling 8psi vacuum at idle.

PART 2, V6 equinox with cfm oil cap. ( 6 cylinder has 24 k Miles on it)
My 2017 V6 equinox, started it up this morning , after it was parked outside all night, low temp of 25 degrees F, it was 35 F when I cold started it
Pop open hood, remove decorative oil cap filter....
And no rattle of cfm vented oil cap, it stayed shut,
since the intake manifold is pulling a vacuum at idle,
thus also putting the crankcase in a vacuum, so the cfm "check valve sealed" the oil cap, not allowing any air into crankcase. (And no air is blowing out when I put my hand on it)
Intake manifold vacuum at idle is 10psi using scan tool
( 10 psi vacuum = negative 10 psi)
And then,
After driving a V6, to warm it up, and letting it idle, pop hood, remove decorative cfm oil cap filter, Checking the cfm oil cap, and again, no rattle, no air escaping out of cfm oil cap, because crankcase is under vacuum because intake manifold is under vacuum under idle since throttle body is closed
thus crankcase is under vacuum ( no air Escaping out of cfm oil cap) ... JUST LIKE it should be according to PCV theory

So here is what I think,
PLEASE COMMENT ===>
1
I don't think the equinox LEA 4 cylinders intake manifold pulls enough vacuum through the "Dirty side internal pcv orifice" at idle, to put the Crankcase in a vacuum...
... even on newer low mile, well maintained 2016's,
and today, even after engine is warmed up, it certainly is not putting the crankcase in a vacuum.
if crankcase was in vacuum it would not expel crankcase gas via vented cfm oil cap
The crankcase is not seeing a vacuum at idle.


And 2
Thus the dirty side PCV orifice must be plugged or has restricted air flow, even after a 50 minute drive on a day where temperature is 45 degrees and sunny, the dirty side PCV orifice is still restricted or plugged.... even on newer equinox.

And 3
the 6 cylinder's "dirty side EXTERNAL PCV orifice " does exactly what it is designed to do.... it puts the crankcase in a vacuum at idle.... since The vented oil cap "is not venting" , it is sealed shut, thus crankcase is in vacuum. <<<===

 

[JayTee2014]

Not being drawn anymore into a discussion of PCV freezing. clogging, short comings that have been posted 2 and 3 years ago before.

Thank you for your viewpoints and investigation.



Readers should know that - - -

In the end it really isn't any different (and more dogmatic about what to do) than what others posted in threads 2 and 3 years ago about what the 2.4L PCV shortcomings in cold weather reveals in particular.


In one week it's a new year everyone ! With more new adventures . :grin:

 

[JayTee2014]

I am actually supposed to be having the pcv cleaned out on my 2015 GMC Terrain, the dealer said it should be done 3-4 years. Guess what, it's only been 2 years and they are telling me to have it done again. The dealer also mentioned on my first clean-out that it is a "poor" design. The check engine light was in January 2022 and I took it to the dealer for an oil change and to run a diagnostic. The dealer said the timing chain needs to be replaced and the pcv cleanout. Not sure how they came to that conclusion without pulling everything apart, which they did not. I had another mechanic look at it and he could not understand why the dealer told me the timing chain needed to be replaced, there was nothing wrong with my timing chain, but at that point, the parts were there and the mechanic was ready to put the new on. Dang dealers & GM.

There are at least 2 simple modifications that can be done on the PCV tube that connects from the valve cover to the air intake your mechanic could do. Search for threads on the forum here and show him.
At least buy and install a GM FC219 vented oil fill cap to try and prevent main seal failure.