2010 LC9 Low Oil Pressure fixed by oil filter

[Bethard728]

1 hour ago, customboss said:

Fantastic feedback for repairing defective components. My point of view after 42 years in the oil analysis and engine R&D business for Cummins is why do we allow the units to get to this point?  

Sure metallurgy is defective from GM and that can be addressed but oil pressure issues is NOT oil flow issues.  

 

Maintaining higher oil pressure just wastes energy if the needed volume is the same. 

 

Aside from the defective valve train or AFM components what is causing the other issues of blockage or deposits? 

 

I would suggest for anyone with a clean, new, or rebuilt engine that maintaining it, repairing defective mechanical issues sure,  but maintaining it so deposits don't block screens, galleries or galleys is the key so no one has to suffer the issues the OP has. 

 

Once again doing repairs is more time consuming, costly, even if it happens 100,000 miles or hundreds if hours down the road than stopping the cause of the damages that can be controlled by proper preventative service.  Nothing will stop defective metallurgy but using better valve train components agreed. 

 

VERY FEW of my oil analysis customers over the years had issues with AFM or DFM systems when we saw issues early and corrected the minor issues or replaced defective components identified by QUALITY OIL ANALYSIS PROPERLY INTERPRETED at very low cost. 

 

Ignorance of the diagnostics available are expensive to correct when its too late. 

 

 

Is oil testing something that you believe should be done on a regular basis?  If it could catch issues like this early, than I am on board with doing it.  I am admitting that I have never thought of oil analysis as a benefit worth the cost, but the situation I am in is a different creature for me.  The truck I am dealing with wasn't bought new by me, but I knew the original owner and it was always serviced on time and with good synthetic oil.  Personally, I have never had this type of issue with a 5.3 before this one, but this is my first AFM engine.  I always changed oil around 3-5K miles and never had an issue.  I sold my old 2003 Yukon to a friend around 250K and it never had a problem.  That particular vehicle ran whatever oil was cheap and always ran Fram cheap filters.  (I am NOT saying that is the right move, but it was what I did when I was younger and poorer).  From the day it was new, I used tech 2000 (I think that was what it was called) from Walmart.  My buddy is still driving it today with over 300K.  I suppose the reason I resisted oil analysis was because I was never in a situation where I thought it would benefit me...but that might not of been the correct outlook to have.

[customboss]

6 minutes ago, Bethard728 said:

Is oil testing something that you believe should be done on a regular basis?  If it could catch issues like this early, than I am on board with doing it.  I am admitting that I have never thought of oil analysis as a benefit worth the cost, but the situation I am in is a different creature for me.  The truck I am dealing with wasn't bought new by me, but I knew the original owner and it was always serviced on time and with good synthetic oil.  Personally, I have never had this type of issue with a 5.3 before this one, but this is my first AFM engine.  I always changed oil around 3-5K miles and never had an issue.  I sold my old 2003 Yukon to a friend around 250K and it never had a problem.  That particular vehicle ran whatever oil was cheap and always ran Fram cheap filters.  (I am NOT saying that is the right move, but it was what I did when I was younger and poorer).  From the day it was new, I used tech 2000 (I think that was what it was called) from Walmart.  My buddy is still driving it today with over 300K.  I suppose the reason I resisted oil analysis was because I was never in a situation where I thought it would benefit me...but that might not of been the correct outlook to have.

I hear ya 5X5!  
We recommended annual analysis to catch wayward problems. 
Engine oil isn’t going to fix all issues but if 

shellac and sludge builds from fuel and oil issues,….a good fuel ,good  oil can slow the development. 
Fram media is exceptional and the lower cost versions can work fine if they aren’t also being loaded with deposits. 
When I did oil analysis for consumers I always asked if this doesn’t find and warn of problems to solve them why do it! 

Edited February 14, 2022 by customboss
My fingers don’t work on iPhone

[Westlotorn]

I have worked on a variety of years and engines, can't say what pump part number I used in each without going back and looking it up.  I chose the high volume option in each, if I did not go with high volume I would keep my stock pump, an oil pump is the most lubricated part inside your engine so they wear very little.  Sometimes the relief spring/piston gets stuck but that can be cleaned out and fixed.  Each of the trucks I repaired came to me broken, I had no control over past maintenance.  My own Yukon has had regular service by me and runs well so far at 125,000 miles.

In each case so far I have been able to fix the engines without overhaul of the long block.  In only one case did I find a dropped valve seat in a 6.0L, 2009 year model.   They are really good engines normally.   FYI:  The AFM system will not activate if oil pressure is below 27 pounds I believe, so there is a minimum requirement and a maximum limit with AFM lifters.   When the AFM lifters stick, the push rod and rocker arm is left loose in the engine with about 3/8" slack so with the lifter still going up and down bouncing these components I could see a push rod getting bent or a rocker arm breaking but I have yet to see that.  Maybe I have been lucky so far.  The best advice, maintain them, if they break, park them and fix them before more damage is done.

[Bethard728]

18 hours ago, Westlotorn said:

I have worked on a variety of years and engines, can't say what pump part number I used in each without going back and looking it up.  I chose the high volume option in each, if I did not go with high volume I would keep my stock pump, an oil pump is the most lubricated part inside your engine so they wear very little.  Sometimes the relief spring/piston gets stuck but that can be cleaned out and fixed.  Each of the trucks I repaired came to me broken, I had no control over past maintenance.  My own Yukon has had regular service by me and runs well so far at 125,000 miles.

In each case so far I have been able to fix the engines without overhaul of the long block.  In only one case did I find a dropped valve seat in a 6.0L, 2009 year model.   They are really good engines normally.   FYI:  The AFM system will not activate if oil pressure is below 27 pounds I believe, so there is a minimum requirement and a maximum limit with AFM lifters.   When the AFM lifters stick, the push rod and rocker arm is left loose in the engine with about 3/8" slack so with the lifter still going up and down bouncing these components I could see a push rod getting bent or a rocker arm breaking but I have yet to see that.  Maybe I have been lucky so far.  The best advice, maintain them, if they break, park them and fix them before more damage is done.

Thank you.  Mine runs and sounds just fine, but loses oil pressure.  I think it will be worth my time to swap in a HV pump and see what happens. 

[Westlotorn]

I went and looked at the part numbers and I would not install the High Pressure version in the AFM engine.   I would not choose the High Pressure pump unless my intent was racing with RPM over 7,000.   Truck engines never see over 6,000 so standard pressure is fine, the High Volume can help hold oil pressure up.   If you are loosing oil pressure you either have a supply problem, the pump is not picking up your oil usually due to a bad O ring or you have internal leaks on the pressure side in the oil galleries.  Maybe AFM Manifold leaks?  I know you installed a new pump already, are you sure you have the right Oring in there sealing that new pump.   Do the oil overfill test and see if your pressure holds.   Add 2 quarts, it can’t hurt to know for sure.

[Bethard728]

41 minutes ago, Westlotorn said:

I went and looked at the part numbers and I would not install the High Pressure version in the AFM engine.   I would not choose the High Pressure pump unless my intent was racing with RPM over 7,000.   Truck engines never see over 6,000 so standard pressure is fine, the High Volume can help hold oil pressure up.   If you are loosing oil pressure you either have a supply problem, the pump is not picking up your oil usually due to a bad O ring or you have internal leaks on the pressure side in the oil galleries.  Maybe AFM Manifold leaks?  I know you installed a new pump already, are you sure you have the right Oring in there sealing that new pump.   Do the oil overfill test and see if your pressure holds.   Add 2 quarts, it can’t hurt to know for sure.

I did replace the O-ring.  Actually did it twice. Once when I did the valvetrain repair and again when I installed the new pump.  I replaced the AFM manifold with a GM unit as well.  I am fairly certain that these are good because the odds of the original doing the same as the replacement is rare.  Especially the O-ring which I have now had 3 in there including the factory.  (I know its not impossible, but unlikely)  I can try the overfill.  I know that's been mentioned, but since I only have issues approx 1500 miles after a filter change, I can't see how that O-ring would be the issue.  I leave the oil in, change the filter, top it back off and its good again for awhile.  If the O-ring was a fail point, I dont think changing the filter would temporarily fix it.

[GhostWriter]

11 hours ago, Westlotorn said:

I went and looked at the part numbers and I would not install the High Pressure version in the AFM engine.   I would not choose the High Pressure pump unless my intent was racing with RPM over 7,000.   Truck engines never see over 6,000 so standard pressure is fine, the High Volume can help hold oil pressure up.   If you are loosing oil pressure you either have a supply problem, the pump is not picking up your oil usually due to a bad O ring or you have internal leaks on the pressure side in the oil galleries.  Maybe AFM Manifold leaks?  I know you installed a new pump already, are you sure you have the right Oring in there sealing that new pump.   Do the oil overfill test and see if your pressure holds.   Add 2 quarts, it can’t hurt to know for sure.

 

More than likely, the problem has more to do with a simple installation mistake than anything.  The pump this particular individual purchased should work OK.  It's just not the best choice for the long term.  Seems like problems cropped up, short term.

 

I purchased, in my opinion, the best gerotor pump for my LC9 application.  Never mind that I chose to remove all of the AFM components, beforehand.  The engine had more than 130,000 miles; so, the M365HV was still the best choice.

 

There's more than one rule that determines the o-ring size.  To be safe, decided to invest in a new Melling pick-up tube.  The relationship between the pump & pick-up tube is what determines the style of the o-ring.  In my case, this meant the stock ring would not be appropriate.  Recall there may have been a mention of some engine de-sludge-a-fication.  Don't recall whether pick-up tube replacement was mentioned.  There weren't many paragraph breaks in the original narrative.  May have misunderstood.  

 

So, if there's a loss in pressure, where is it coming from?   In my case, the unnecessary pan relief valve bore was fitted with a plug.  Then, this very simple pump was disassembled to check for defects.  No scoring in the pump relief valve bore was observed.  After that, the pump was properly shimmed even though many claim this step is unnecessary.  No perceived loss in pressure, after re-assembly.  There again, I chased, then blew-out every oil passage I could find.

 

By removing the AFM components, these engines become much simpler to troubleshoot, when necessary.  That would be my recommendation to anyone who is willing to perform their own wrench work.  Want to reduce the variables?  Keep things simple.

 

 

 

 

Edited February 16, 2022 by GhostWriter

[Westlotorn]

There are 3 unique O ring designs I have seen, I think Melling ships the pump with two, Red and Blue?   I have also seen a black one, they all measure unique so somehow you need to verify your O ring is sealing.  The extra oil in the pan trick would rule out an Oring problem but you can’t leave it that way for long term use.

 

[GhostWriter]

41 minutes ago, Westlotorn said:

There are 3 unique O ring designs I have seen, I think Melling ships the pump with two, Red and Blue?   I have also seen a black one, they all measure unique so somehow you need to verify your O ring is sealing.  The extra oil in the pan trick would rule out an Oring problem but you can’t leave it that way for long term use.

 

 

According to my notes, the Melling M365HV came with a black & green o-ring.  Neither would have worked properly.  The Melling pick-up tube came with the red o-ring.  Melling's rule sez to use the o-ring that is pre-installed on the pick-up tube, regardless of what is stipulated in the pump instructions.  Of course, this means more than one o-ring will work with the pump; but, only one o-ring is ideal for a particular pick-up tube.  This means the outside diameter of the rings are about the same.  The inside diameter & thickness of the o-rings is what's important.  The tube design is what makes all the difference.  There are at least three. 

 

All of this was verified prior to assembly.  As a retired skilled-trades machinist/metrologist, old habits are hard to break. 

 

Edited February 16, 2022 by GhostWriter

[Westlotorn]

If the distance from the pan to the oil screen is too close the pump will not pull enough oil.  I would have to look it up but there is an accepted range of clearance.  I know these bolt in place in the 5.3L and are not adjustable like the older engines but obviously something is being missed in your set up.  Why it can run 1,500 miles before losing oil pressure is a real mystery pointing to something being very odd.   Maybe your oil flow is so marginal that a slightly dirty filter is enough to drop below a threshold and triggers your low oil pressure.  Let us know what you find.

[Bethard728]

7 hours ago, GhostWriter said:

 

According to my notes, the Melling M365HV came with a black & green o-ring.  Neither would have worked properly.  The Melling pick-up tube came with the red o-ring.  Melling's rule sez to use the o-ring that is pre-installed on the pick-up tube, regardless of what is stipulated in the pump instructions.  Of course, this means more than one o-ring will work with the pump; but, only one o-ring is ideal for a particular pick-up tube.  This means the outside diameter of the rings are about the same.  The inside diameter & thickness of the o-rings is what's important.  The tube design is what makes all the difference.  There are at least three. 

 

All of this was verified prior to assembly.  As a retired skilled-trades machinist/metrologist, old habits are hard to break. 

 

I don't recall which O-ring I used.  I might be able to go look into the left over gasket kit parts and see whats left.  I did some research at the time to choose what I thought to be the correct one, but really dont remember where I landed.  I believe my pump came with a blue and green but another gasket kit came with red and I think that is the one I ended up using because it seemed like the best fit on the pickup tube.  

 

Something that I have not mentioned since I started.  There was absolutely zero sludge buildup anywhere in this engine.  Even under the screen in the sending unit.  I'd consider it one of the cleaner engines that I've had apart.

 

I have several projects ahead of the truck right now as long as it keeps ticking.  Next time it drops pressure and I have some time, I will do the added oil test and see what happens.  If that doesnt change things, then I will swap in the HV pump. 

 

Thanks to everyone for the help.