Low oil pressure with P0014 and P0016

[emedlin]

Drove the Envoy around town today. And I noticed the check gauges light flash and the DIC said low oil pressure. Only said low oil pressure at idle. It didn't say to shut the engine off, just low oil pressure. Engine sounded fine. My code reader also pulled P0014 and P0016. Could be old could be new codes. I cleared them to see if they come back. For the low oil pressure I am assuming it is the oil pressure switch and plan to change it. Could the other codes have anything to do with low oil pressure warning, or do I need to replace the CPAS?

The truck isn't drove much. Maybe a 100 miles a week if that normally. And with COVID shutdowns it has been driven even less.

This is an 04 XUV 4.2L with over 200K miles on it.

 

[Mike534x]

If the engine doesn't sound like its knocking, then its most likely a bad oil pressure switch. Its common to see them fail eventually.

Your first code would be for the CPAS (Camshaft Position Actuator Solenoid, AC Delco Part # 12615873), its part of the VVT and usually fails when the solenoid is clogged. It does have little mesh screens so you could attempt to clean it, but they usually break free so its usually better to just replace it. The P0016 is more then likely connected to the CPAS sensor. The solenoid (looks like a tube sticking out) sits above where the upper radiator hose meets the inlet on the left side of the engine. If I remember correctly, you need to unbolt the Power Steering Pump to access the bolt that allows you to remove the CPAS.


Since you're going in to replace the CPAS, it wouldn't hurt to do the CPS (Camshaft Position Sensor (#213-1557). It sits at the front of the engine, under the valve cover. There's just one bolt holding it in, and the Power Steering Pump has to be removed to access it as well. Its a cheap enough part, and saves you from doing it later on down the road if/when it goes next.

 

[Mooseman]

Both codes could be related to a bad CPAS. We used to say to try and clean it but for the trouble of getting it out, just replace it. You could give the Cam sensor a cleaning since it's easy to access that one and replace it if necessary.

However, this is dependent on good oil pressure. If you replace the oil pressure switch and it still gives a low oil pressure warning, you may have deeper issues. Also check the switch's wiring.

 

[TJBaker57]

As Mooseman said, these secondary codes are possibly a result of the oil pressure issue. So a little more on this oil pressure switch. I believe you already know it is a switch, not a sensor in the sense that it does not read a variable amount of pressure, just a fixed setpoint. Anything seen on the dashboard gauge is a calculation from PCM based on RPM etc. The thing that surprised me on my 2002 is that the switch is closed at no oil pressure and opens the circuit at or above adequate pressure. For some reason I would have expected the opposite. As a proof one can disconnect the switch then observe the dash gauge which then shows pressure even with the engine off! Additionally start the engine and watch the "pressure" rise and fall with RPM while the switch is disconnected! Some folks have said that if oil leaks into the connector it can influence the reading. I don't think this is true as motor oil is not a conductor. But leaking oil from the sensor is nonetheless a sign of a failed switch. When I first experienced this low oil pressure thing it was immediately after having oil changed. I suspected the oil they used but I replaced the switch which was leaking anyway as well as checked the pressure with a test gauge kit and also installed an aftermarket mechanical oil pressure gauge. That was a little more that 3 years ago. I still see the occasional low oil pressure warning but in my case it is primarily at startup in the winter and the temps are below freezing. I am relatively certain my primary ussue is a leaking oil pickup tube seal. It took me a few years to come to accept that the "normal" idle oil pressure for this engine is just 12 psi. I suspect this may also have influenced the manufacturers decision to not install a true sensor. I can only imagine the amount of complaints of low oil pressure they would have gotten if the actual pressure was accurately displayed.

 

[emedlin]

Ordered the ACDelco D1843A oil pressure switch and Lisle 13250 socket to remove it. Also ordered some mystery oil. Figured it could use some cleaning after all theses miles. Probably won't get to install it until the 25th. But, I will update this post with the results. Hopefully that's all it needs.

 

[emedlin]

Changed the oil sensor. No codes yet, but it still flashes low oil pressure at idle sometimes. The sensor did have oil in the electrical connection. Waiting on mystery oil. Maybe that will clean things up and help.

 

[emedlin]

Well I did get the P0014 code again while driving around, but I don't really think they are related. Also figure it isn't worth worrying about until I figure out the low oil pressure warning. Still sounds and runs smooth.

 

[mrrsm]

High Mileage GM Atlas 4.2L Engines invariably suffer from a lot of Combustion Chamber Blow-By that allows the Products of Incomplete Combustion to infiltrate into the Oil Supply in the Crank-Case...and decorate EVERYTHING it can cling to with Gas-Gum Lacquer. In particular, the Oil Pick-Up Tube Screen falls prey to this problem the worst... and in some cases, with dire consequences for the Health of the Engine.

For the sake of brevity and efficiency... I snagged a Screen Print of a 12 Point List covering "How to Properly Flush the Oiling System in ANY Engine". I'm including an image of the LL8 Oiling System that I edited in color to properly display how the system is designed... and to hi-lite the Key Items of concern to you.

Please note that besides the Clogging of the Oil Pick Up Tube... a Sketchy "O" Ring between the Gerotor Oil Pump Flange and the insert point of the Oil Pick Up Tube into the Engine Block area can fail by breaking the necessary Vacuum Seal needed to draw oil up from the lower Oil Reservoir. This event can allow Compressible Air to enter the Oil Pump and Oil Passages leading to the Engine Bearings and cavitate from time to time, causing dramatic drops in Oil Pressure, sometimes with catastrophic results.

 

[Mooseman]

P0014 may be related. If the cam phaser is unable to move the cam angle properly due to low oil pressure, it could throw this code, same as a defective phaser or CPAS. If it's still giving low pressure warnings at idle, I would check the actual pressure with a test gauge.

 

[emedlin]

So, I did some reading up on engine flushes. Man the opinion seems to be all over the place on what works and what doesn't and if you should even do it if you don't have a problem. ATF from what I have read doesn't have more detergent than modern oils based on what I have found and isn't recommend for that reason, but instead use a real engine flush product. Assuming you think you need a flush.

Any thought on a engine flush product for the I6? I assume there is at least some engine build up after 200+K miles and if the I6 suffers from Blow-By. Not sure if that is bad assumption or not though. My current oil life is at 50% and it looked pretty black when it leaked out during the sensor change.

As for the P0014, that makes sense. Maybe it will go away when the low oil pressure warning is fixed. Unfortunately I don't have a test gauge to check the actual oil pressure.

 

[gmcman]

What oil are you using and what is your drain interval? How long has this oil been in the motor? Are you using synthetic? Have you tried a new oil filter, doubtful it's clogged but worth a try.

One thought is possible deposits on the cam phaser causing it to stick.

Edit: We replied at the same time. If you are going to try to flush the oil system, I would recommend a slow cleaning. You could either try Liqui-Moly 2004 Lifter Additive, substitute 1qt of Marvel Mystery Oil, or try Auto Rx.

 

[TollKeeper]

For engine flushes, this is what I recomend, but it is an expensive engine flush, and has to be bought at specific locations.. And sometimes it is hard to come by.

This is what to start with..

BG Dynamic Engine Cleaner

As Step 1 of two, this potent cleaner thoroughly cleans the crankcase and the entire lubrication system.

www.bgprod.com

And then on the 3rd and final oil change, use this..

BG Advanced Formula MOA^®

Oil fortifier that keeps piston rings from sticking, stabilizes oil viscosity, prevents increased exhaust emissions, reduces wear, prevents sludge and varnish, and is resistant to evaporative oil loss.

www.bgprod.com

Its a longer than normal flush system. You drain the oil, and put in a cheap quality oil filter. Then put in the Dynamic Engine Cleaner (its 6 quarts), and then let the engine run at 3000rpm for 45 minutes (make sure your cooling fan works correctly!). At the end, you immediately change the oil and filter. Once the new filter is on, and drain plug is in, you put the Engine rinse in, and again run the engine at 3000rpm for 20 minutes. At the end, same process, drain the oil and change the filter immediately. Put in your quality oil filter of choice, the MOA oil, and your preferred oil (to full line).

Heres a vid of a guy doing the process on a new gen Camaro.

I would bet your 2 codes are related to oil pressure issues. Im not much on the 4.2, but been doing a lot of research on the 3.6HF, which is MUCH more sensitive.

Do I think the engine flush above is going to help? Honestly, no, not unless your oil pressure gauge is just wonked out, and you actually have good oil pressure. But usually once low oil pressure is indicated, and verified on a engine, its only going to lead to one ultimate outcome. Rebuild/Replacement. But here again, its just my opinion.

 

[emedlin]

I actually saw that video yesterday just before you posted it. Waiting for the next part when he goes back into the engine and looks at it. But, from what he showed in that video it looks like it really cleaned it.

As for oil changes, I take it to a quick lube place because it is quick and easy. Last oil change was about 6 months ago. Around 50% oil life right now. It normally gets changed every 10 months or so. I don't know the brand of oil. Probably some cheap high mileage dino oil though.

My 2 quarts of Mystery Oil came in yesterday. Maybe I should just put one quart in. Run it for say 100 miles (few weeks based on how much it is driven now), then drain it and add some good synthetic oil, another quart of Mystery Oil, and new oil filter. Thoughts? If that doesn't work have a shop look / give me an estimate as all other low oil pressure reasons seem to be very involved to fix. More than I can take on unless I am missing something else easy to try.

As I don't have an oil gauge I would need to buy one or get a shop to check it. Not sure what that would cost. But, considering I have changed the sensor I can probably assume it is truly low. Might be 1 psi low or 5 psi low though as there is no way of knowing with the stock setup.

 

[gmcman]

As for oil changes, I take it to a quick lube place because it is quick and easy. Last oil change was about 6 months ago. Around 50% oil life right now. It normally gets changed every 10 months or so. I don't know the brand of oil. Probably some cheap high mileage dino oil though

If you aren't paying extra for synthetic then you can likely bet you are getting some dino oil.

First thing I would do is change the oil filter, even if you didn't change the oil, but I would recommend an oil change now before you put any additives in your motor.

I don't like to assume but you don't know how long that filter has been in there.

Changing to a synthetic now means you run the slight risk of picking up a small leak but that depends on the health of your motor and seals, so don't be scared to use it.

Pick up a few oil filters, PF61E AC Delcos would be fine, and be ready to change them early if needed.

I personality wouldn't drive it another inch without the very least changing the oil filter. A fresh oil change of 5W-30 would serve you well.

The fact you may have a sticky cam phaser seems more likely now.

Edit to add: You need to pay close attention to the oil pressure, this also points to a possibly compromised oil pick up screen as spoken earlier by @MRRSM .

If you cannot remedy the oil presssure problem from either a new filter or sensor, verifying by a gauge, then a cleaning of the oil pick up screen may be necessary.

They also make sandwich adapters for the oil filter to use a pressure gauge.

 

[emedlin]

Thanks. I will try and get time to change the oil this weekend. Plan to put in some Pennzoil Ultra or Pennzoil High Mileage. Leaning toward the high mileage for the seal conditioners.

As for the oil filter how would I know to change it earlier, besides my low oil pressure? Can you really even see in them to tell if they need changing if you pulled it to look?

 

[gmcman]

As for the oil filter how would I know to change it earlier, besides my low oil pressure? Can you really even see in them to tell if they need changing if you pulled it to look?

Honestly in your case you wouldn't really know to change it earlier. There is a bypass valve that allows for oil passage around the filter in case of a restriction/over pressure.

I have to assume that it's working and your issue is elsewhere and not the filter.

The only reason I suggest changing the filter is because it's a quick, cheap, and a non-invasive option and worth a try.

That being said, a true pressure test is first and foremost.

 

[mrrsm]

If the Oil Filter from your LAST "Quick Oil Change" is still in the Motor... I'd be tempted to perform an Autopsy on it and see if that place was being Honest. If you find an excessive amount of Debris in between the Filter-Folds after dropping the components into a White Plastic Bucket, it will be EZR to see what is left in the bottom.

Use Kerosene and a Machinist's Parts Brush to clean out inside of the dis-assembled Oil Filter Body and in between the Paper Fan-Fold Corrugated Filter Sections and you'll have a better notion if they did their Job. The two places inside of the GM 4.2L Engine that will Dump Oil Under Pressure right back into the Crankcase if there are any Blockages are:

(1) The Over-Pressure By-Pass Valve in the Oil Filter Manifold which is designed to prevent the Oil Filter Canister from BURSTING from any Excessive Oil Pressure generated at Very High RPM:



(2) The Spring Loaded Plunger Oil Pressure Relief Valve in the Upper Pressure Chamber of the Gerotor Oil Pump designed to allow Oil Under Pressure to escape the Gerotor Gearing if it exceeds around 65 PSI.



@MAY03LT demonstrates How to Install and Use an Analog Oil Pressure Gauge on the Atlas Vortec 4200 Engines to read ACTUAL Oil Pressure in his Three Part Series:

 

[emedlin]

Got the 6 quarts of Pennzoil and 1 quart of MMO in today. I didn't slice open the old oil filter though. However, so far so good. No drips on the driveway and no codes. Will see how it does over the next week or so. I only drive about 50 or so miles a week in it. Any thoughts on how long I should run it before the next oil change. Seems you can leave MMO in it until the next oil change.

 

[gmcman]

I would take a peek at the dipstick every 500 miles or so, note the color of the oil. Hard to say, but given the symptoms, I personally would probably change it after about 2K miles.

At the next change, also try some Lubri Moly Hydraulic lifter additive, or the BG MOA.

Hopefully you don't run into any pressure issues. If so, that's when I would consider draining the oil again or an early oil filter change.

You could get an oil filter sandwich adapter, install an electrical sending unit, and keep a gauge handy if you don't want a permanent gauge install.

Earls and Mishimoto are more pricey, Glow Shift has one also that's a bit cheaper. I have the Glow Shift adapter, works well, just need to ensure you have a good wrap of teflon tape on the sensor threads and make sure the sensor is a little more than snug. The Earls is probably more robust but I have no regrets.

 

[emedlin]

So, far I have only put about 25 miles on the new oil. Today at a stop light I saw the low oil pressure warning again. It only flashed up a few times at the light. It didn't stay on. However, when I got it home I let it sit in the drive for a few minutes idling and it never came on. I don't see any error codes either. And there are no oil spots on the drive way.

I know 25 miles isn't really anything, so I hope after some more time it will get better. It runs really quite now. Maybe the quietest it has ever been. Not that it was loud or rough sounding before.

Any reason you recommend the Lubri Moly Hydraulic lifter additive or the BG MOA? I have another quart of MMO that I was planning on putting in it on the next oil change.

 

[gmcman]

The liqui moly can be beneficial for cleaning the areas with tight clearances.

Is your XUV 2WD or 4WD? If 2WD, removing the oil pan is a far easier job than the 4WD.

If you do have a clogged oil pick up screen or faulty pick up tube seal, it sounds like your motor would be right at the point where you could address this issue and hopefully make everything right.

 

[emedlin]

It is 2WD. Although still more than I can probably do. Any clue what it cost to have some one clean the pick up screen and check the seal? Although first I would have them check the actual oil pressure. Although I doubt the new sensor I put in is bad.

 

[mrrsm]

A Small Fortune at the Dealership ...and any Professional Mechanic Worth his Salt would not take less than $1,500.00 due to the exhausting amount of Labor and the fact that with NO common experience performing the work... the cautious learning curve required would be steep...and very necessary to avoid screwing things up.

Remember... BOTH the Front Timing Cover AND the Crankcase would have to come off the Engine if the intent here was to upgrade to the Later Version of the Gerotor Pump with the Better Seal Grommet and the need to also obtain the New Melling Oil Pickup Tube that ALSO requires the Updated Gerotor Pump to be replaced.

GM Sells the New Design of the Pump and Timing Cover as a complete assembly for under $150.00. Anyway... If you want to eyeball what these differences are... Visit this link to my "Flickr-Bucket" Album for fairly good views... and Parts Comparisons:

GM Atlas 4.2L LL8 Engine Gerotor Oil Pump

This Album shows Images of the Autopsy of a Late Model GM 4.2L LL8 Gerotor Oil Pump.

www.flickr.com

 

[gmcman]

I agree it's a big job to remove the timing chain cover. If you just wanted to check the oil pickup tube and remove the tube for cleaning, then it would be only the oil pan and lower the steering rack.

The crossmembers are the easy part, on a 2WD model using the correct sockets and extensions for the steering rack is a small learning curve to get that out of the way, then removing the pan isn't too big of a deal. On the 4WD versions that's a whole different ball of wax.

I would surely want to know what the true pressure is before I tackled the job, especially if the motor is quiet.