oil pressure drops

[Kenneth Walker]

2007 suburban 5.3 AFM delete already done. I had one lifter collapse and did the delete now when cold I have 35 P.S.I. but when hot with 5w30 oil pressure drops to 5 P.S.I. I've replaced rods and mains cam bearing's, put the lingenfelter rivets in the towers, replaced the pump 3 times, changed the cam retainer plate, oil pressure switch, different oil filters multiple times. I turned up the idle when in gear to keep the oil pressure at 10 P.S.I. when idling. now to keep the oil pressure around 35 when cruising I'm running 15W40 I know that is some thick oil for the truck but it's either that or I get a range performance code for oil pressure and yes the oil pressure is correct I have hooked up a manually gauge multiple times. how would I check and see if the towers are leaking internally or if the bar bell is bad it sad for 6 months why I was doing the delete I had to get money together to fix it.

[Jsdirt]

Looks like you covered most problem areas.  Only thing it could be at this point is trash in a passageway, restricting flow to the pressure sender, and whatever else that circuit keeps alive. As you probably know, there's a screen below that sender. Loves to plug up on ones that weren't maintained well. Since you did the delete, you can toss that screen in the trash.

 

Here's yet another of many reasons I hate this engine ...

[Kenneth Walker]

JSdirt the valley cover is the one with the O-rings I don't have the factory vlom valley cover anymore. do you have any ideas of how something would get clogged just because of a dropped lifter and the screen has been gone when I originally changed the sensor I checked for one and there wasn't one in it

[Jsdirt]

Could be that the failed lifter made metal, which found its way into a passageway. They usually do. They also usually wipe the cam out too, which makes quite a bit of metal. If it were me, I'd just run the heavy oil and hope the light is out when inspection time rolls around. If you have no such inspections, I wouldn't worry about it one bit. The amount of labor to tear into the engine again isn't worth it if the oil pressure is actually good. Put 2 layers of Gorilla tape over the light, and call it a day. Run it until it grenades, and thank GM for the aggravation.

 

Bottom line is, an engine shouldn't be this friggin complicated and failure prone. GM SUCKS for designing the LS this way! So many pitfalls. We went from the 350 that could run 300k + miles being neglected its entire life, to this. The first LS engines weren't as bad - the top end components were 10x better. From '07 on, they went way down hill. As a mechanic, I refuse to fix lifter failures on the LS. I recommend a crate engine from an engine builder, or I won't even touch it. It's not worth the trouble to me, even if I charge $2k for the job, because 9 times out of 10 you'll have problems afterwards. I've seen guys spend 30 hours working on these things, only to have a cam bearing walk out of its bore 3k miles later, or the .50 cent o-ring fails in the pickup screen, and the whole engine and all the new work becomes scrap in less than 5 minutes. It's a marriage I want no part of. I've seen far to many fellow techs get bit in the ass by this poorly engineered disaster of an engine.

 

Sorry for the rant, but this crap pisses me off! It's EVERYWHERE today, with every brand, and every piece of equipment, on or off road. So tired of seeing it and hearing of it. Seems the whole country lately is trying to see who can be first to the bottom of the barrel, like a snowball headed for hell ... but I digress.

[Grumpy Bear]

13 hours ago, Jsdirt said:

Sorry for the rant, but this crap pisses me off! It's EVERYWHERE today, with every brand, and every piece of equipment, on or off road. So tired of seeing it and hearing of it. Seems the whole country lately is trying to see who can be first to the bottom of the barrel, like a snowball headed for hell ... but I digress.

And he sticks the landing folks. That's 10's across the board.

 

 

And the worst cost more.

 

OP, did you measure the lifter bores when you did the conversion?

[Kenneth Walker]

I did not measure the bores but the roller or nothing like that was bad it just collapsed that's why I did the conversion when I get home in October from Antarctica  I'm taking the engine back out and going through the whole thing again this time I'm going to take the bottom end to my machine shop and have him rebuild it and mic everything to make sure everything is ok and I do have inspections I can pass them I clear it before I head there and all the parameters are set to pass emissions. it is aggravating with the AFM crap they are good engines but how much money I have in the delete and if you add my hours of tearing into it over and over again I should have bought a new engine and just did a delete on it before it went in I would have saved a lot of money

[Grumpy Bear]

Good plan. What I'm reading is some clearance is out of spec and pressure is bleeding off. Check, check and triple check. 

[Kenneth Walker]

yea its just weird because before the lifter collapsed and while it was before I tore it apart it had good oil pressure do y'all think it could be the barbell maybe from how long it was sitting it dried out and causing some oil to bypass

[CamGTP]

Maybe the oil pressure relief valve on inside the oil pan is causing an issue too. Just a guess.

[Jsdirt]

Another good one - easy to overlook the obvious over the net. With all the damn acronyms we have to remember on these modern junks it's no wonder I forget the basics ... 

[Kenneth Walker]

yea i bypassed the pressure relief originally then ended up taking my oil pan off my 6.0 and putting it on the truck thinking something was messed up with the pick up tube or something so i swapped the oil pan and the pick up tube and it still didn't change anything and the 6.0 was not a AFM motor so it didn't have the pressure relief inside the pan

[pokismoki]

On 4/15/2021 at 3:26 PM, Kenneth Walker said:

I did not measure the bores but the roller or nothing like that was bad it just collapsed that's why I did the conversion when I get home in October from Antarctica  I'm taking the engine back out and going through the whole thing again this time I'm going to take the bottom end to my machine shop and have him rebuild it and mic everything to make sure everything is ok and I do have inspections I can pass them I clear it before I head there and all the parameters are set to pass emissions. it is aggravating with the AFM crap they are good engines but how much money I have in the delete and if you add my hours of tearing into it over and over again I should have bought a new engine and just did a delete on it before it went in I would have saved a lot of money

i think you need to measure your lifter bores, i'm sure this also effects the oil pressure numbers. has the engine been living on funky 0-20 weight oil all its life?  i've seen lots of rocker arm failures on FCA products , they all use 0-20, and the oil film strength may not be up to the task to handle the loads

Edited April 17, 2021 by pokismoki

[Kenneth Walker]

I'll Mic the lifter bores when I get home and I take the engine back out and no this has been a 5w30 engine its whole life until after the AFM problem when I went to 15w40

[pokismoki]

3 hours ago, Kenneth Walker said:

I'll Mic the lifter bores when I get home and I take the engine back out and no this has been a 5w30 engine its whole life until after the AFM problem when I went to 15w40

can you data log the oil pressure pid on a scanner?

 

i doubt this is the issue but wasn't there a redesigned and updated 22psi BOV oil filter for our engines.? might want to convert to those if your not using already.

 

the 15w40 sounds interesting, what is the ambient temps where you use this oil?

[Kenneth Walker]

I didn't know about the updated oil filter but I have used acdelco filters on this engine since I found out about the oil filters causing problems and yes I can the pid is correct with the gauge and the manual gauge I have put on it. I'm in North Carolina so its up and down in the winter I switch to 10w30 but the summer I have been switching to 15w40 and I don't take a chance on going on any long hauls