Oil Pressure

Bill Technician Rosetown, Saskatchewan Posted   Latest   Edited  
Discussion
GM Truck Tech Chat
2009 GMC Sierra 1500 SLT 5.3L (3 LC9) 6-spd (6L80)
Oil Pressure

Truck comes in with low oil pressure. Warmed up and then got 24 PSI@ 1000 RPM 35 PSI@ 2000 RPM 38 PSI@ 3000 RPM. 8 PSI idle in gear (On the scan tool). Changed oil/filter used a coat hanger to pull as much sludge and dirt out of the bottom of the pan as possible to reduce new filter plugging. Warmed up and then got 35 PSI@ 1000 RPM 42 PSI@2000 RPM and 46 PSI @3000 RPM 21 PSI @ idle in gear. It is almost always the oil and filter here with sludge. All specs with PF63 oil filter and Petro-Canada 5W-30 Dexos1 gen2 oil.

I have noticed that when the ethanol content faults high and fills the crankcase with fuel the filter media must constrict, loosen up sludge, thin out the oil or all of the above because oil pressure codes and that issue almost seem married to each other. I know this is nothing new, but it's a GM Truck Tech Chat so......

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Jamey Owner/Technician
Ventura, California
Jamey Default
   

Hi Bill, good stuff ! I recently had a 2004 Avalanche with a 5.3 that would start and have 45-50 PSI, after running the engine (cold start or hot) you could watch the pressure start to drop. Within 20-40 second, it was at 2 PSI!! No knock, no lifter noise. I confirmed the pressure with a mechanical gauge. I found that the oil galley to the sender and the bottom of the sender was plugged with…

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Bill Technician
Rosetown, Saskatchewan
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Thank you Jamey, That would have been an 07'+ 5.3 no? I used to always do a pre and post filter gauge reading lots of documentatiom etc. (See pic for pre filter) GM test step one literally has you remove the problem for testing... Yikes! Now I just change the oil and filter for the most part with basically the documention I have posted here. I also tell them to change their oil more regularly…

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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I just happen to have a vehicle that came in with DTC's for the VVT. I believe it was P0014 and P0017 but I will have to look. Ran good for a couple miles then acted up to the point you might have to pull over. Shut it off and let sit 10 or 15 seconds and then re start and you would be good for another couple miles. I also have scope captures of the issue as it was doing it. I will have to dig…

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Bill Technician
Rosetown, Saskatchewan
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Nice Spence. Looking forward to it.

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Glen Owner/Technician
Arthur, Illinois
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Jamey, Just in case you don't already know the oil pressure sender and screens on the pictured Gen LS motor can be done without pulling the intake. I use the Lisle 13200 and a bolt for the screen.

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Jamey Owner/Technician
Ventura, California
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Thanks for the tip Glen. Unfortunately that motor has to be replaced due to some main bearing failure. The Main was coming apart and flakes of bearing were missing. The engine was prone to very short trips, had an excessive amounts of clear water condensation in the crankcase.

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Glen Owner/Technician
Arthur, Illinois
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Bill, Do you always run the PF 63 even through the EPC calls for the PF48E?

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Bill Technician
Rosetown, Saskatchewan
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Yes. Always, for the last 4 years approximately. I should have said PF63E. As a fact it has greater capacity and is less likely to plug between oil changes. As an opinion the higher bypass pressure prevents VLOM and lifter latch issues due to bypassing. Sort of a 2 part issue in my opinion. In almost all cases here low oil pressure is caused by a plugged oil filter. Yet the result is…

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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We have stopped using ACDelco filters at least 4 or 5 years ago or more.

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Bill Technician
Rosetown, Saskatchewan
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Fair enough. The E core is a poor design. I have seen more E core failures than anything else. Although never on LS/LT engines. I have seen big name filters one way valves deteriorate, and had multiple fuel filter failures damage fuel systems and they had 0 accountability for any damage they caused. The 0 accountablility and not fixing known issues with their product is the part that turned me…

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Exactly why I no longer use ACDelco is the quality! I was one of the TSS shops for 15 years. I watch the product quality drop and drop. Not just oil filters. As far as warranty I don't play that game. I prefer to use and do a better service for my customers and myself and not have the warranty issues in the first place. I also do not see where the filter we use nor the other parts would void…

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Bill Technician
Rosetown, Saskatchewan
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Spence, What is your combination of oil and filter that has worked for you? If GM found foreign material passed through or a different bypass pressure etc. on the filter shipped back with the engine that could turn into an issue.

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Well it wasn't ACDelco and using a better service interval and filter won't let it happen. ;)

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Bill Technician
Rosetown, Saskatchewan
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Sounds like you have quality customers, that don't "forget" I think 1st owner issues travel over on used vehicles that have not been mainained and are still under the warranty period... Even if they are okay. That crud seems to work out for a while. I hear you though. The delco oil filters have room for improvement.

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Blame it on the PF48E you are taking off.

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Bill Technician
Rosetown, Saskatchewan
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Fair.. and extended intervals, and sub par oil, and a pressure washer in the oil pan, and low oil. Really no much going for these rigs as far as their recommended service goes.

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Glen Owner/Technician
Arthur, Illinois
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"Sub par oil" I am guessing you are referring to something besides Gen 2 Dexos?

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Bill Technician
Rosetown, Saskatchewan
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I am. I have been pretty happy with my gen 2 stuff from experience. I am not so sure about gen 1. I don't actually have a lot of experience with that oil. I think a lot of places were just running whatever was the cheapest bulk oil they could buy in them.

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Had a little bit more time sooooooo... Back to this comment of yours. For the most part I do have quality customers. They don't always have to remember as we send out reminders and/or when they come in our work order system reminds us and we inform them.

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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As promised. This vehicle was losing oil pressure due to sludge around pick up tube screen.

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Bill Technician
Rosetown, Saskatchewan
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What was the route cause of the sludge do you think Spence?

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Following the suggested oil change intervals when the oil change reminder suggested on the IPC. Vehicle was used for short trip deliveries.

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Bill Technician
Rosetown, Saskatchewan
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Yes. Not a good idea to follow that. What do you find works well for a schedule in your region on these trucks?

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Depends...

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Glen Owner/Technician
Arthur, Illinois
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LOL I present my customers with GM's OLM schedule as an option... Or My OLM which is designed to protect my customer's vehicle :) They choose

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Bill Technician
Rosetown, Saskatchewan
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What does it depend on? Do you have some examples?

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Glen Owner/Technician
Arthur, Illinois
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Fist off Kevin McCartney has tons of info on this already and is way more knowledgeable then me so I would recommend starting there. IMO Oil level/oil consumption: Most customers don't like to check their oil, with no leaks adding more then 1 qt. between LOF just seems like a waste of good oil. The smell,look & feel of oil that is drained is another indicator. One of the ways I think of…

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Spencer Owner/Technician
Jeffersonville, Pennsylvania
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Short trip vs long trips. Extended idle in which case we check hours. Vehicles with carbs vs fuel injection. Conventional oil vs semi synthetic vs full synthetic. 3,000 miles to 5,000 and/or 3 to 6 months.

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