Oil leaking into cold air intake?

Hello BBOYLILROB

The part number you sent me for the passenger side has a different baffle. In the bulletin they only show an upgraded part for the driver's side, which you have. There was nothing done to the passenger side. The number you sent me looks like the old version. I'm wondering if this is what might be causing the issue.

Looks like it's got 2 big holes in it and nowhere for the oil to drain well enough. If this is the case drilling those holes, we talked about earlier might fix the issue.

Thank you,
Brendon

Hello BBOYLILROB,

Okay. Let me look around some more to see what I can find out for you. See if there are any other TSB's or redesigns.

The vented oil cap we talked about earlier might fix the issue. P/N 12589430. Or at least reduce it.

I found one for you here:
https://www.gmpartsdirect.com/oem-parts/gm-engine-oil-filler-cap-12589430

But like I said let me look around a little more for you and see if I can find anything else.

Thank you,
Brendon

There is a PCV valve in that fitting, sounds like his is stuck open and it's sucking in oil under heavy vacuum. It also sounds like it's pulling a lot more vacuum through the crankcase than it should be. Check that the intake air side is open and that the valve is okay, he mentions it attaching to the cold air intake that doesn't sound correct. Also reference TSB PIP3343F.

Hello BBOYLILROB,

Is this the intake and tube you used to have?

Thank you,
Brendon

Good morning, BBOYLILROB,

This is true. So, it shouldn't be the cold air intake. I mean everything is brand new. I don't see how replacing valvetrain components with OEM parts would cause this issue. I mean hoses and valve covers are new too. Maybe it's a low vacuum issue? When you did this job, I am assuming you replace the intake manifold gasket as well, right?

If there is an intake leak anywhere, manifold gaskets, map sensor grommet, evap tube grommet or throttle body gasket, it would cause low vacuum and it would affect the PCV System. You probably left the throttle body on when you removed the intake so that gasket should be fine but the maybe a bad seal or gasket somewhere. Most of the time you would notice performance issues or rough idling but not always. Sometimes it can leak with no noticeable symptoms. It may be just big enough to cause lower vacuum, causing the PCV System to malfunction but not enough to turn on the engine light or cause drivability issues.

I was also thinking for now using that oil catch can you had on the driver's side on the passenger's side will at least slow it down for now.

I remember you saying you were consuming a gallon and a half of oil per hour when towing. Is that right? I might have mis-read.

Thank you,
Brendon

Hello BBOYLILROB,

Can you tell me what the issue was that led you to remove the heads and do all this work in the first place? Maybe it will help shed some light on what's going on.

Also, I added an image of a K&N intake for your engine. Can you tell me if this is the set-up you have?

When you have a chance.

Thank you,
Brendon

Hello BBOYLILROB,

Okay. Thats a lot of good information. Thank you.

How long since the injector was replaced? Has the engine light been on since?

Your engine, the L92, doesn't have Active Fuel Management (AFM), which has been known to cause oil consumption issues in these motors because apparently it destroys the rings.

But it does have Variable Valve Timing (VVT). They use an actuator in the end of the camshaft the controls valve timing. Excessive valve overlap can also cause a "fake" lean condition because oxygen is being pushed down the exhaust and the O2 Sensor is seeing it as unburned air, so it thinks it is lean.

Anyone ever say anything about the cam or VVT or cam phasers when you were going through all this?

Valve overlap issues can also increase crankcase pressure which could explain why oil is being pushed into the intake.

Thank you,
Brendon

Hello BBOYLILROB,

Absolutely. Let me see what I can find for you.

Thank you,
Brendon

Good morning, BBOYLILROB,

At idle you should be at 18-22 inHg at sea level. Your vacuum will decrease about 1" per 1000 ft of elevation. So, if you are at 2,000 ft above sea level 16-20 inHg will be normal for you.

Some engines may have 15-17 inHg at sea level.

At load you should be closer to 0 inHg and slowly rise.

The unit inHg, stands for inches of mercury, which is how vacuum is measured. Your scan tool might be able to change the unit because I think it is going to give you a reading in kPa.

If so, at idle and at sea level you should have about 60-74 kPa.

Here is a kPa-inHg Calculator:
https://convertlive.com/u/convert/inches-of-mercury/to/kilopascals#22

Here is a decent vacuum gauge kit:
https://www.tooldiscounter.com/product/mityvac-vacuum-pressure-gauge-and-fuel-pump-tester-mitmv5511?msclkid=4d10c819bb8013f3db35ac9c57cf793b

If the MAP Sensor is dirty, it could read lower.

An analog gauge on the brake booster line or you could also use a tee at the PCV port on the intake would be better. This way all vacuum lines are connected.

You are going to want to get it up to operating temp and look at it at idle, low cruise (1800-2200 RPM) and high cruise (2500-3000 RPM) for about 15 seconds. Let your foot off the gas. The vacuum reading should jump as the throttle closes. Sometimes to up to around 25 inHg.

Here is a good article about the process which has a lot of other good information in it:
https://www.motor.com/magazine-summary/mastering-the-basics-reading-a-vacuum-gauge/#: :text=Run%20the%20engine%20at%20idle%2C%20low%20cruise%20%281800,and%20watch%20the%20gauge%20as%20the%20speed%20drops.

Another expert also suggested we measure crankcase pressure. Excessive crankcase pressure can push oil out of the engine so I agree it is something we should definitely test as well.

He suggested using a pressure transducer on the dipstick tube, but you will need a waveform viewer to get the measurement. This is the most accurate way, but a waveform viewer is very expensive.

There is another way I found I think is worth a try. It's using something called a manometer and the oil cap. You could get an oil cap from the boneyard, make sure it has a good seal and attach a fitting to it.

The meter is about $50. HVAC techs use them to measure gas pressure at your furnace.

Here is a link to one:
https://www.amazon.com/Manometer-Professional-Pressure-Differential-Measuring/dp/B07CWQJD6D/ref=asc_df_B07CWQJD6D?tag=bingshoppinga-20&linkCode=df0&hvadid=80814160006525&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584413736956691&psc=1

Here is a video of someone doing this test:
https://youtu.be/8AcvKPYFeDI

It is on a mini, but the theory is the same.

Since the oil is coming out of the valve cover with the oil cap is I think this would be a good place to test.

From what I have found max pressure should be 2.5 to 6.0 psi.

I would also perform a compression test. Your engine is chugging oil, so I want to make sure there isn't an issue with the piston rings. You can rent a tester at a local auto parts store, but they get thrown around and can be very inaccurate. They are pretty cheap, so I would just get a new one. It's a good tool to have.

Here is a link to a decent one that is inexpensive:
https://www.harborfreight.com/compression-test-kit-8-piece-62638.html?utm_source=bing&utm_medium=cpc&utm_campaign=425671834&campaignid=425671834&utm_content=1154488236059904&adsetid=1154488236059904&product=62638&store=639&msclkid=22c0e3b9ea1c1ae7a06e873c3ed78f35

For a spec so far all I can find is:
No cylinder should be below 100psi
No cylinder should be less than 70% of the highest cylinder reading

I think performing these tests will give us some insight as to what might be going on.

When you get home and rest your bones a bit, I would perform these tests. I will guide you through them.

Once we get some measurements, we can take them and start looking at specific areas.

Thank you,
Brendon

Cold air intake creates more vacuum and pulls more air than the system is designed for, causing excessive crankcase vacuum? Have him put a vacuum gauge on the oil dipstick and raise the rpm, see what he gets. This would be a good time to put a pressure transducer on the dipstick and scope the readings.

Reading his later responses the intake he installed isn't set up for PCV, there are two different versions of that engine, the heavy duty version doesn't use the external PCV system. That would be the intake he installed that doesn't have the PCV fitting. On those the rest of the parts are not used either as the intake handles the PCV functions internally. Looking at his other responses it sounds like he has run the PCV line to the intake, but that fitting is supposed to be the fresh air intake connection and the air then goes into the engine and out to the intake fitting that he doesn't have. Not sure how to rig that system up with the mixed parts.

Only other thing I can think of would be if by some fluke it cracked a ring and gouged a cylinder wall. That much oil use would show up in massive leaks if it's engine internal pressure, the front and rear crank seals would be dumping oil like waterfalls if the pressure in the block rises by hardly anything at all. Might try a leak down test to at least get a read on the condition of the rings and bores. Think I read he used all stock parts? If so I can't think of a reason it would suddenly start using oil unless something odd occurred, the 6.2 isn't really known as an oil burner, even when they are well worn.