2010 LC9 Low Oil Pressure fixed by oil filter

customboss · February 7, 2022

5 hours ago, Bethard728 said:

Who do you recommend? I have never sent off an oil sample before. Also, is there a standard test? or what should I ask them to look for? Thanks,

Jeff, I recommend contacting the site sponsor Nick at Synthetic Advantage he has access to some cutting edge affordable oil analysis. In this case get an Advanced test so you get a good overview of what is going on inside your LC9.

You can PM him at Black02Silverado.

Also: http://www.syntheticadvantage.com

Edited February 7, 2022 by txab

Bethard728 · February 9, 2022

I just wanted to follow up since I have seen no responses about my last post regarding the 355 vs 365 pump. After talking again to Summit, I have found that the M355 is indeed the correct pump that has the upgraded pressure meant for the demands of the AFM and/or VVT aluminum block engines. It does everything the M365 does and also comes with the high pressure spring. This IS the better replacement pump. The other option is to get the M355HV which has an additional (approximately) 20% over the M355 (which already has 33% over the original ironblock pumps.) If I had known this last year, I would have went with the HV version.....but the whole hindsight story.

kdittbenner · February 10, 2022

im having same issues. I cleaned the screen under the pressure switch, I had a mechanical guage T'd into the pressure port and they both would go down to 6-8 PSI. pull off the side of the road and shut it down. start back up go to 30 PSI and slowly drop back to under 10PSI. when i pulled the screen I dropped the oil, and filter. ran a hose to the pressure port, poured some seafoam in the port and blew it back down to the oil filter to make sure no junk left in the oil galley. I did remove the mechanical gauge from the pressure switch port and put it in the port just below and behind the power steering pump. i have maintained 50 ish PSI on the gauge at this port even when losing pressure at the top of the engine. It has to be the oil filter, or the pressure regulator in the oil PAN is leaking.

I had oil pressure issues with this truck 50K miles ago. at that time i put in a new oil pump, Pickup Oring, installed the oil deflector on the regulator in the oil pan, and did the piston ring cleaning procedure. have not had an issue since.

if i remove the oil filter, is there a way to direct air to blow through the oil pressure relief in the oil pan? is there anything at the top of the engine that has a gasket to create oil pressure? here is my thinking. when the oil pressure drops the engine does not change sound- no tapping, ping, clatter. that is telling me there is still oil flow.... the oil needs a restriction to create pressure. does that make sense?

Edited February 10, 2022 by kdittbenner

GhostWriter · February 11, 2022

On 2/9/2022 at 8:28 AM, Bethard728 said:

I just wanted to follow up since I have seen no responses about my last post regarding the 355 vs 365 pump. After talking again to Summit, I have found that the M355 is indeed the correct pump that has the upgraded pressure meant for the demands of the AFM and/or VVT aluminum block engines. It does everything the M365 does and also comes with the high pressure spring. This IS the better replacement pump. The other option is to get the M355HV which has an additional (approximately) 20% over the M355 (which already has 33% over the original ironblock pumps.) If I had known this last year, I would have went with the HV version.....but the whole hindsight story.

Just waded through all this.

Believe it's very important that we don't continue to confuse the M355 with the 10355. They are two completely different animals. For an AFM application, I would only consider 4 Melling pumps:

M365...............standard pressure, standard volume.

M365HV..........standard pressure, high volume

10355...............high pressure, standard volume

10355HV..........high pressure, high volume

Summit was able to sell a more expensive pump, but it's not the best choice for your application. Standard pressure is more than enough for a stock application. For this application, rule of thumb is to hold out for more volume.

Only one clear winner, here: M365HV. If the famous George from Melling was here, I bet he'd back me up.

In George speak, thanks for clicking.

Bethard728 · February 11, 2022

18 hours ago, GhostWriter said:

Just waded through all this.

Believe it's very important that we don't continue to confuse the M355 with the 10355. They are two completely different animals. For an AFM application, I would only consider 4 Melling pumps:

M365...............standard pressure, standard volume.

M365HV..........standard pressure, high volume

10355...............high pressure, standard volume

10355HV..........high pressure, high volume

Summit was able to sell a more expensive pump, but it's not the best choice for your application. Standard pressure is more than enough for a stock application. For this application, rule of thumb is to hold out for more volume.

Only one clear winner, here: M365HV. If the famous George from Melling was here, I bet he'd back me up.

In George speak, thanks for clicking.

This helps, thanks. I assumed, incorrectly, that the 10355 was referred to as 355. I do know for sure that my 10355 pump came with the standard pressure spring but included a high pressure also, which I installed. So, in my case, the 10355 was a standard pressure, standard volume until I changed the spring. It's very possible that in some cases it comes factory loaded with the high pressure spring though.

The question I would like answered is what is equivalent to the factory installed pump? The 10355 was identical in size, thickness, and appearance when compared to the OEM pump that came out of my truck. (other than maybe some part numbers) The reason I ask is that someone in an earlier post said something similar to "that little ironblock pump is not doing you any favors" and stated that I had the wrong pump in my truck. I am assuming that "standard pressure" on all of the pumps mentioned above have the 33% increased volume when compared to the older ironblock pumps. The bottom line for me is that I should of done more research and went with one of the HV pumps. The good news is that the oil pumps are a breeze to change....the bad news is that there is cost associated with buying another pump and getting the truck aligned again. (I have not found a way to get the steering rack back in the same place in the past)

Bethard728 · February 11, 2022

23 hours ago, kdittbenner said:

im having same issues. I cleaned the screen under the pressure switch, I had a mechanical guage T'd into the pressure port and they both would go down to 6-8 PSI. pull off the side of the road and shut it down. start back up go to 30 PSI and slowly drop back to under 10PSI. when i pulled the screen I dropped the oil, and filter. ran a hose to the pressure port, poured some seafoam in the port and blew it back down to the oil filter to make sure no junk left in the oil galley. I did remove the mechanical gauge from the pressure switch port and put it in the port just below and behind the power steering pump. i have maintained 50 ish PSI on the gauge at this port even when losing pressure at the top of the engine. It has to be the oil filter, or the pressure regulator in the oil PAN is leaking.

I had oil pressure issues with this truck 50K miles ago. at that time i put in a new oil pump, Pickup Oring, installed the oil deflector on the regulator in the oil pan, and did the piston ring cleaning procedure. have not had an issue since.

if i remove the oil filter, is there a way to direct air to blow through the oil pressure relief in the oil pan? is there anything at the top of the engine that has a gasket to create oil pressure? here is my thinking. when the oil pressure drops the engine does not change sound- no tapping, ping, clatter. that is telling me there is still oil flow.... the oil needs a restriction to create pressure. does that make sense?

This is exactly the way mine started. It would lose pressure, but shutting it down and restarting would cause it to go back up for awhile. My first thought was oil not getting back to the pan in time, but why would that change with a filter. To answer your question about blowing into the pressure relief. If memory serves me correctly, the pressure relief is immediately behind the oil filter housing and, in theory, you could blow into the port. However, I'm not sure you could get enough pressure to blow off the pressure relief because it will also backfeed through the pump and into the pan. I can't think of anything that would stop the backflow of air that direction.

I completely agree that it has to be the filter or relief valve since you have pressure before the filter, but not after. In my case, I have been through over a dozen filters, so its not really possible that all of my filters have malfunctioned...so the relief valve makes sense. Whatever actual issue is causing the pressure loss, surely it could be mitigated by removing and plugging the relief valve. And what issue could be caused by plugging it? I wonder if it would have enough pressure to blow out the filter? That would be interested to see if I can plug it and find out what would happen.

GhostWriter · February 12, 2022

6 hours ago, Bethard728 said:

This helps, thanks. I assumed, incorrectly, that the 10355 was referred to as 355. I do know for sure that my 10355 pump came with the standard pressure spring but included a high pressure also, which I installed. So, in my case, the 10355 was a standard pressure, standard volume until I changed the spring. It's very possible that in some cases it comes factory loaded with the high pressure spring though.

The question I would like answered is what is equivalent to the factory installed pump? The 10355 was identical in size, thickness, and appearance when compared to the OEM pump that came out of my truck. (other than maybe some part numbers) The reason I ask is that someone in an earlier post said something similar to "that little ironblock pump is not doing you any favors" and stated that I had the wrong pump in my truck. I am assuming that "standard pressure" on all of the pumps mentioned above have the 33% increased volume when compared to the older ironblock pumps. The bottom line for me is that I should of done more research and went with one of the HV pumps. The good news is that the oil pumps are a breeze to change....the bad news is that there is cost associated with buying another pump and getting the truck aligned again. (I have not found a way to get the steering rack back in the same place in the past)

GhostWriter · February 12, 2022

I usually only log in once or twice a year. You wouldn't want to bet the farm on anything I say, or suggest.

Seems like multiple requests for an oil analysis have been suggested. So far, no results have been published.

Wow. Consider how many components have already been changed out, per the OP. Then, consider what it takes to properly evaluate the dumbel. Still, no oil analysis.

So, we spin a lifter which may, or may not, damage a cam or lifter bore. Then, we replace the components expecting to reclaim an engine in its original condition. There are reasons why some mechanics will not warranty these kinds of engine repairs. You never know, for sure, what's actually lurking in those oil passages.

We have testimony that everything seems to go wrong @ around 1500 miles; but, these observations don't seem very scientific, to me.

I know what I would do in this case; but, doesn't seem like the OP wants to listen.

Good luck.

Edited February 12, 2022 by GhostWriter

kdittbenner · February 13, 2022

OK, this is what i did, and next oil change i will send a sample. It gets cold here, Minnesota. I started the truck, let idle for a minute. truck was outside over night. i put it in Tow mode and drove it, got RPM up to 4000, pressure after the pump got to 80, top of the engine was 50ish. I was thinking it would make the pressure relief in the pan open and push any junk out the relief. well, from what i can tell it worked. i have put 300 miles on the truck the last 3 days. pressure has not gone below 20psi at idle. Last week i would lose pressure in the first 5 to 8 miles. i lost pressure 3 different trips in a row. hope this can help someone else. Thanks for the help.

Bethard728 · February 13, 2022

On 2/11/2022 at 9:19 PM, GhostWriter said:

I usually only log in once or twice a year. You wouldn't want to bet the farm on anything I say, or suggest.

Seems like multiple requests for an oil analysis have been suggested. So far, no results have been published.

Wow. Consider how many components have already been changed out, per the OP. Then, consider what it takes to properly evaluate the dumbel. Still, no oil analysis.

So, we spin a lifter which may, or may not, damage a cam or lifter bore. Then, we replace the components expecting to reclaim an engine in its original condition. There are reasons why some mechanics will not warranty these kinds of engine repairs. You never know, for sure, what's actually lurking in those oil passages.

We have testimony that everything seems to go wrong @ around 1500 miles; but, these observations don't seem very scientific, to me.

I know what I would do in this case; but, doesn't seem like the OP wants to listen.

Good luck.

Sounds like you are doing us all a favor by only logging in once or twice a year. I assume that is because it takes you that long to save up enough rude comments. It sounds like you are one hell of a keyboard mechanic and should be really proud of yourself. I don't recall ever saying that I expected the engine to be like original condition. I measured the lifter bores and inspected the cam so I am fairly confident that is not my problem. The components I replaced, other than the oil pump, were all parts I would of replaced anyway when servicing the lifters and AFM system....so I don't see the reason for "Wow. Consider how many components have already been changed out". Your next statement is what clued me in to the fact that you are a wicked keyboard mechanic...."Then, consider what it takes to properly evaluate the dumbel." What is there to consider??? Dropping the transmission and T-case to replace it and change the rear main seal at 180 some thousand miles?? We are talking a couple hour job here that requires no skill. It was a quick little project that I did with my son one afternoon.

I will admit that I failed to conduct a proper scientific protocol....but to be fair, I didn't realize that I needed data backed by science. It is a general statement saying it happens around 1500 miles after a filter change. It might happen at 1012 miles or it might make it 1853 miles....I don't think that the exact mileage really makes a difference.

As far as oil analysis goes, I will fully admit that I havn't been thrilled about doing it. I couldn't see how it was an oil issue since leaving the oil in and changing the filter restored my pressure for about the same amount of miles. (I apologize that I didn't keep a scientific log) I was thinking that the suggested analysis was to identify dilution by fuel, which I was confident enough that was not the problem. Recently a suggestion was made to get an oil analysis to look for other things that could point to other issues. This makes sense to me and will get an oil analysis the next time I lose oil pressure.

I have a mechanic friend that warned me about asking for help on a forum. He commented that "a bunch of non-mechanics playing like they know ****** from Shinola" will be all that you get. I was pleasantly surprised that was not the case with this forum. Up until GhostWriter crawled out from under his keyboard to add a bunch of useless comments to the post, I was impressed with the knowledge and willingness to help. GhostWriter, you are the exact type that gives these forums a bad name. Good luck with all that you do and any of your scientific endeavors, but feel free to leave your rude comments to yourself if you can not contribute anything worth while.

KARNUT · February 13, 2022

Iv some experience in water getting in the oil. Although my oil pressure did drop some it wasn’t anymore than usual when oil gets old. You can tell when there’s water in the oil by sight. Same with gas by smell. There always it’s getting overfull. Oil analysis shouldn’t be needed in those instances. I’m kinda lazy these days. I fixed my water in oil with bars leak. As long as an oil filter changed fixed the problem for a reasonable time period. That would be my fix.

Edited February 13, 2022 by KARNUT

Westlotorn · February 14, 2022

I have not posted on this Forum in quite a while but I can share a couple things I have experienced with the 5.3L and 6.2L engines. I have fixed about 10 of these now. I have deleted the AFM twice with good results. On all the others I went back to the OEM design with a fully functioning AFM system. All so far have come out perfect. All have had good oil pressure after the repair even though several had zero or near zero oil pressure before the repairs.

I have done years between 2003 and 2011 with mileage between 135,000 and 210,000 miles. I use the Melling High Volume pump. I like 60 PSI running hot on the road. The engine is fine with only 40 PSI hot but I shoot for 60, personal choice. I also like more than 30 at hot idle. Hot idle oil pressure will be lower depending on how loose your Main and Rod bearings are and how loose your cam bearings are. Internal oil leaks kill oil pressure.

I always use the GM AFM manifold, I have been afraid to try any of the other brands due to the amount of labor involved if one does not work as expected. I won't say any of the other brands are good or bad, unless I see several people have used them for years and trust them I stay with OEM. The AFM manifold itself can be a major oil leak internally and offer low top end oil pressure. I don't know what brand you installed or if you just used your old one in your repair.

For the new lifters I trust Sealed Power, which I believe are made by Top Line who purchased the Sealed Power / Johnson Hylift Lifter plant and has it operating again in Michigan. I think Melling and a couple other companies also sell the HyLift lifters, both the standard and AFM version. Sealed Power used to own Johnson Lifters, Johnson used the trade name HyLift, Top Line purchased that plant so any of these names are the same lifter. I have had 100% good luck so far with these. Again with this much labor, pulling both heads, why risk using a lower priced part. I see the Ebay and Amazon knock off parts for 1/2 this price but those are buyer beware parts in my opinion. If you see a brand offering these AFM lifers at 1/2 price you should be cautious. Good lifters cost more.

The secondary oil relief valve in the oil pan can be a major leak also, I always replace that valve and the O'ring on the oil pump. Check the screen in the oil pump to make sure it is not blocked. Some Yahoo's turn wrenches and use excess silicon to seal surfaces. That excess can end up in your oil pump screen and block flow. I like the trick of using extra oil as a test to see if the oil pump Oring has failed.

When I eliminate the AFM system, I remove the secondary oil relief valve and plug it. This secondary valve is in there to limit your oil pressure. I was told if oil pressure in AFM engines exceeds 70 PSI the oil pressure can cause the AFM lifters to activate so the extra pressure relief was added to AFM engines. On cold start oil is thick and oil pressure will spike well above your standard pressure relief spring setting in the oil pump.

With this said, I would not install a High Pressure Spring or pump into a AFM engine. I have added boosters to the factory spring to add a "little more than factory stock oil pressure but again, my goal is 60 PSI Hot when above say 1,500 RPM and when doing AFM repairs I always keep the AFM secondary relief valve in the pan but I do install a new one. Most of these trucks have an oil leak somewhere around the oil pan or the oil cooler lines or cover so I always pull the pan and see all these parts before starting the truck with the new lifters and AFM system. I also use Fel-Pro gaskets, this is not an advertisement, just stating what has worked with zero failures. IF your internal leaks are minor the high volume pump will supply enough flow to keep your oil pressure higher and mask the leaks. I hope something here helps you fix yours.

PS: When looking for an internal loss of oil pressure we sometimes resort to pulling the oil pan, then hook up what we call an oil pig, real name is an engine Pre Oiler, these hold 5 quarts of oil and you hook up your air hose to pressurize the system, The Pig attaches to your Oil sender location. I use 40 PSI of air to move the oil, more air will push the oil in too fast and cause problems. The Oil pig will push 5 quarts into your engine in about 1 minute so you have to work fast to see where your oil is leaking, it makes one hell of a mess but in odd cases it does show the exact location of your leak. A large tub under the engine will catch most everything. Drips and even fast drips are normal from your engine bearings when pressurized. If you find a stream of oil you found a major leak. Usually we would find it was in the Cam bearings or sometimes you found one of the oil gallery plugs was flat missing in that engine.

This test was only used when like yours, the problem would not show itself so you could repair it. On the AFM engines if the AFM manifold could be your leak. I would have to study the layout of the oil drains and think this out. The oil would end up in the lifter valley and drain down on the camshaft lobes. Would be hard to identify location when looking up from down below. In the old small blocks this test would clearly show a cam bearing leak but in the AFM engines the leak could be the afm manifold dripping down on the cam.

Edited February 14, 2022 by Westlotorn

Bethard728 · February 14, 2022

5 hours ago, Westlotorn said:

I have not posted on this Forum in quite a while but I can share a couple things I have experienced with the 5.3L and 6.2L engines. I have fixed about 10 of these now. I have deleted the AFM twice with good results. On all the others I went back to the OEM design with a fully functioning AFM system. All so far have come out perfect. All have had good oil pressure after the repair even though several had zero or near zero oil pressure before the repairs.

I have done years between 2003 and 2011 with mileage between 135,000 and 210,000 miles. I use the Melling High Volume pump. I like 60 PSI running hot on the road. The engine is fine with only 40 PSI hot but I shoot for 60, personal choice. I also like more than 30 at hot idle. Hot idle oil pressure will be lower depending on how loose your Main and Rod bearings are and how loose your cam bearings are. Internal oil leaks kill oil pressure.

I always use the GM AFM manifold, I have been afraid to try any of the other brands due to the amount of labor involved if one does not work as expected. I won't say any of the other brands are good or bad, unless I see several people have used them for years and trust them I stay with OEM. The AFM manifold itself can be a major oil leak internally and offer low top end oil pressure. I don't know what brand you installed or if you just used your old one in your repair.

For the new lifters I trust Sealed Power, which I believe are made by Top Line who purchased the Sealed Power / Johnson Hylift Lifter plant and has it operating again in Michigan. I think Melling and a couple other companies also sell the HyLift lifters, both the standard and AFM version. Sealed Power used to own Johnson Lifters, Johnson used the trade name HyLift, Top Line purchased that plant so any of these names are the same lifter. I have had 100% good luck so far with these. Again with this much labor, pulling both heads, why risk using a lower priced part. I see the Ebay and Amazon knock off parts for 1/2 this price but those are buyer beware parts in my opinion. If you see a brand offering these AFM lifers at 1/2 price you should be cautious. Good lifters cost more.

The secondary oil relief valve in the oil pan can be a major leak also, I always replace that valve and the O'ring on the oil pump. Check the screen in the oil pump to make sure it is not blocked. Some Yahoo's turn wrenches and use excess silicon to seal surfaces. That excess can end up in your oil pump screen and block flow. I like the trick of using extra oil as a test to see if the oil pump Oring has failed.

When I eliminate the AFM system, I remove the secondary oil relief valve and plug it. This secondary valve is in there to limit your oil pressure. I was told if oil pressure in AFM engines exceeds 70 PSI the oil pressure can cause the AFM lifters to activate so the extra pressure relief was added to AFM engines. On cold start oil is thick and oil pressure will spike well above your standard pressure relief spring setting in the oil pump.

With this said, I would not install a High Pressure Spring or pump into a AFM engine. I have added boosters to the factory spring to add a "little more than factory stock oil pressure but again, my goal is 60 PSI Hot when above say 1,500 RPM and when doing AFM repairs I always keep the AFM secondary relief valve in the pan but I do install a new one. Most of these trucks have an oil leak somewhere around the oil pan or the oil cooler lines or cover so I always pull the pan and see all these parts before starting the truck with the new lifters and AFM system. I also use Fel-Pro gaskets, this is not an advertisement, just stating what has worked with zero failures. IF your internal leaks are minor the high volume pump will supply enough flow to keep your oil pressure higher and mask the leaks. I hope something here helps you fix yours.

PS: When looking for an internal loss of oil pressure we sometimes resort to pulling the oil pan, then hook up what we call an oil pig, real name is an engine Pre Oiler, these hold 5 quarts of oil and you hook up your air hose to pressurize the system, The Pig attaches to your Oil sender location. I use 40 PSI of air to move the oil, more air will push the oil in too fast and cause problems. The Oil pig will push 5 quarts into your engine in about 1 minute so you have to work fast to see where your oil is leaking, it makes one hell of a mess but in odd cases it does show the exact location of your leak. A large tub under the engine will catch most everything. Drips and even fast drips are normal from your engine bearings when pressurized. If you find a stream of oil you found a major leak. Usually we would find it was in the Cam bearings or sometimes you found one of the oil gallery plugs was flat missing in that engine.

This test was only used when like yours, the problem would not show itself so you could repair it. On the AFM engines if the AFM manifold could be your leak. I would have to study the layout of the oil drains and think this out. The oil would end up in the lifter valley and drain down on the camshaft lobes. Would be hard to identify location when looking up from down below. In the old small blocks this test would clearly show a cam bearing leak but in the AFM engines the leak could be the afm manifold dripping down on the cam.

Thank you so much for the reply!! This is what I was hoping to find here; someone that has fixed the problem. After reading your reply, I'm hoping I can fix mine with the HV version of the oil pump. I used Felpro gaskets and everything else, except for the oil pump, were GM parts. I am very thankful that you mentioned the start up oil pressure activating the AFM lifters! I never thought of that happening if I were to plug the relief valve in the pan.

Do you recall which pump you used? There seems to be some confusion on the difference between M365 and 10355. After talking with Summit and researching on the internet (which we know is 100% the true, every time) They are both standard volume, standard pressure unless you change the spring, which you could do in either. I did not think to ask about the HV versions of each but I would assume that the 10355HV would be considered the better unit.

Thanks again for taking the time to reply! I'm excited to hear from someone that has actually fixed the problem!

customboss · February 14, 2022

7 hours ago, Westlotorn said:

I have not posted on this Forum in quite a while but I can share a couple things I have experienced with the 5.3L and 6.2L engines. I have fixed about 10 of these now. I have deleted the AFM twice with good results. On all the others I went back to the OEM design with a fully functioning AFM system. All so far have come out perfect. All have had good oil pressure after the repair even though several had zero or near zero oil pressure before the repairs.

I have done years between 2003 and 2011 with mileage between 135,000 and 210,000 miles. I use the Melling High Volume pump. I like 60 PSI running hot on the road. The engine is fine with only 40 PSI hot but I shoot for 60, personal choice. I also like more than 30 at hot idle. Hot idle oil pressure will be lower depending on how loose your Main and Rod bearings are and how loose your cam bearings are. Internal oil leaks kill oil pressure.

I always use the GM AFM manifold, I have been afraid to try any of the other brands due to the amount of labor involved if one does not work as expected. I won't say any of the other brands are good or bad, unless I see several people have used them for years and trust them I stay with OEM. The AFM manifold itself can be a major oil leak internally and offer low top end oil pressure. I don't know what brand you installed or if you just used your old one in your repair.

For the new lifters I trust Sealed Power, which I believe are made by Top Line who purchased the Sealed Power / Johnson Hylift Lifter plant and has it operating again in Michigan. I think Melling and a couple other companies also sell the HyLift lifters, both the standard and AFM version. Sealed Power used to own Johnson Lifters, Johnson used the trade name HyLift, Top Line purchased that plant so any of these names are the same lifter. I have had 100% good luck so far with these. Again with this much labor, pulling both heads, why risk using a lower priced part. I see the Ebay and Amazon knock off parts for 1/2 this price but those are buyer beware parts in my opinion. If you see a brand offering these AFM lifers at 1/2 price you should be cautious. Good lifters cost more.

The secondary oil relief valve in the oil pan can be a major leak also, I always replace that valve and the O'ring on the oil pump. Check the screen in the oil pump to make sure it is not blocked. Some Yahoo's turn wrenches and use excess silicon to seal surfaces. That excess can end up in your oil pump screen and block flow. I like the trick of using extra oil as a test to see if the oil pump Oring has failed.

When I eliminate the AFM system, I remove the secondary oil relief valve and plug it. This secondary valve is in there to limit your oil pressure. I was told if oil pressure in AFM engines exceeds 70 PSI the oil pressure can cause the AFM lifters to activate so the extra pressure relief was added to AFM engines. On cold start oil is thick and oil pressure will spike well above your standard pressure relief spring setting in the oil pump.

With this said, I would not install a High Pressure Spring or pump into a AFM engine. I have added boosters to the factory spring to add a "little more than factory stock oil pressure but again, my goal is 60 PSI Hot when above say 1,500 RPM and when doing AFM repairs I always keep the AFM secondary relief valve in the pan but I do install a new one. Most of these trucks have an oil leak somewhere around the oil pan or the oil cooler lines or cover so I always pull the pan and see all these parts before starting the truck with the new lifters and AFM system. I also use Fel-Pro gaskets, this is not an advertisement, just stating what has worked with zero failures. IF your internal leaks are minor the high volume pump will supply enough flow to keep your oil pressure higher and mask the leaks. I hope something here helps you fix yours.

PS: When looking for an internal loss of oil pressure we sometimes resort to pulling the oil pan, then hook up what we call an oil pig, real name is an engine Pre Oiler, these hold 5 quarts of oil and you hook up your air hose to pressurize the system, The Pig attaches to your Oil sender location. I use 40 PSI of air to move the oil, more air will push the oil in too fast and cause problems. The Oil pig will push 5 quarts into your engine in about 1 minute so you have to work fast to see where your oil is leaking, it makes one hell of a mess but in odd cases it does show the exact location of your leak. A large tub under the engine will catch most everything. Drips and even fast drips are normal from your engine bearings when pressurized. If you find a stream of oil you found a major leak. Usually we would find it was in the Cam bearings or sometimes you found one of the oil gallery plugs was flat missing in that engine.

This test was only used when like yours, the problem would not show itself so you could repair it. On the AFM engines if the AFM manifold could be your leak. I would have to study the layout of the oil drains and think this out. The oil would end up in the lifter valley and drain down on the camshaft lobes. Would be hard to identify location when looking up from down below. In the old small blocks this test would clearly show a cam bearing leak but in the AFM engines the leak could be the afm manifold dripping down on the cam.

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.

KARNUT · February 14, 2022

All this very interesting. In the real world of the busy working person who usually doesn’t do their own oil changes. Let alone the repairs. Their going to go by the manual maintenance. Oil changes with synthetics usually are north of 100$ especially when you change some other suggested maintenance items. Don’t forget to rotate those tires. Now tell them in order to make it 100K miles you need to double that or even triple the maintenance. All that after dropping 50K on their ride. If they were smart enough to buy extended warranty. There’re going to go by the book. Once they calculate all the extra time and money to make their ride last past the warranty. They’ll say screw it and probably change brands. If they didn’t buy extended warranty and the engine fails they’d probably stuff a salvage yard engine in. Probably from a shop that doesn’t bother to report to car check and trade it in.