2003 2500 HD 6.0L with low oil pressure problems. Please Help! - Page 2 - Chevrolet Forum - Chevy Enthusiasts Forums

2003 2500 HD 6.0L with low oil pressure problems. Please Help!

Built_NotBought's Avatar
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September 15th, 2011, 10:41 AM   #11  
6.0 oil pressure issues

Hey I just wanted to pass this on to you guys. 90% of oil pressure issues Ive found on these 6.0 engines is the O-ring between the oil pump & pickup tube..They deteriorate or sometimes are partially torn from factory ..This causes low oil pressure due to air getting pulled in with the oil..Also on cold startup it will take along time to pickup oil causing noisy lifters ect..If you notice your oil pressure gradually gets higher as the engine gets warmer you can bet the o-ring is the culprit..I always change the PUMP and the O-ring together though because its already apart so a fresh oil pump & a timing chain is just a good idea ..UNLESS your under 150k on the odometer...We are seeing 300,000 to 500,000 miles out of these with proper maint & good synthetic oil!!! My 6.0 just turned 290,000 miles yesterday..GO CHEVY!!!

Last edited by Built_NotBought; September 15th, 2011 at 10:47 AM.
Airstar's Avatar
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March 1st, 2015, 5:36 PM   #12  
I realize I am about 1 year late but I would like to add clarity for those who follow. I had the same issue, no oil pressure when oil was cold but outstanding pressure once motor warmed up. This was my work vehicle(still is) so I had a lot of hard thinking to do. My vehicle has 223,000 on it. Buy or not to buy? (new, that is) My6.0L Vortec was running strong despite the oil issue. I took it to my local Goodyear who changed my oil and filter and installed a new oil sensor. Same problem. Considering the scope of work involved in replacing the pump I opt'ed to get a quote. I've done this work since before I could legally drive but today I run a heating and cooling business and don't have the time to do this. 1. Got quote. To replace oil pump $1000. I am beginning to think spend the money on a new van. 2. I thought, crap, I will have to do this job to justify keeping it. So, I thought I would do the water pump, timing chain and gears and oil pump. 3. Then, I caught my breath, thought it through and came to the realization that 1. My problem "HAD" to be the O-RING in between the pick up tube and the pump. Did I really need to replace everything else? In my case? No. My motor , no matter how well it is running, probably wont be real dependable after 300,000. Will the timing chain break in the next 75, 000? I googled it and couldn't find anything on them breaking. So, I did not have transfer cases or anything in my way, I dropped the pan and replaced the o-ring. I will not bore you with clean up and torque proceedures. The o-ring left residue inside the pump socket and on the tube it slides onto. I used the only solvent I had available which was acetone to clean it off. I coated some food grade lubricant on the o-ring before inserting the pick up tube. Took my time cleaning up the pan etc. You will need the o- ring, new pan gasket and the external cooler lines gasket. It worked. On single digit mornings I now have awesome oil pressure. The job wasn't bad at all. The new stee/neoprene gaskets are a synch. I am going to post some picks if it works. New and old gasket. The old gasket was once green. The green was what I washed off the oil pump and pick up tube w/acetone. My motor started having this problem around 220,000. It was sucking air around the o-ring when the oil was at its thickest. once it warmed and thinned, the pump would draw it up instead of pull air around the o-ring. I hope this has helped and I appreciate everyone else's help that steered me in the right direction.
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george57's Avatar
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May 1st, 2015, 8:18 PM   #13  
i have 10 psi on a new oil pump on my 2003 2500hd just installed it a couple hours ago?????? im stuck dont know what to do please help!

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May 2nd, 2015, 11:25 AM   #14  
New engine.

Dude I did everything everybody said from the cheapest till it got expensive$$$ flush the engine, the oil sending unit, the oil pump,the oil gage, TILL I REBUILT THE ENGINE!!! It turned out the oil pump is bullet proof!! But the problem that was exposed was,THE CAM BEARING!!! The last cam bearing was beat up and I was loosing oil pressure thru the last bearing . In order to get to it u have to pull the engine cuz it to long to be pull thru the fire wall !! And the tools you need to replace the cam bearing it's easier to pull the engine,I also replaced the cam ,to a tow cam for better mileage since I was already in there ! Look it up on you tube on replacing the cam it will show you the tools you need, I paid to get it done . Sorry about the bad news and good luck cuz it's gonna hurt about 6k!!! /B]
Posted By: jonhan I have a 2003 Chevy 2500 HD (75k miles)and the "oil pressure low" chime comes on daily. I have changed the sending unit it didn't change anything. I have done a pressure test and I have about 8 psi @ 1000 rpms (the recomended minimum is 8 psi). There aren't any knocks or any other problems, but the pressure probably should be higher and the chimes are driving me crazy. Any ideas? The truck is also bifuel (cng), but I don't know if that makes a lot of difference.


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May 4th, 2015, 11:45 AM   #15  
Why did you change the pump to begin with? Same issue? 10 psi ? Did you get the o-ring onto the pick up tube w/o damaging it? If you had the same problem before did you inspect your pick up tube for splits, that one sounds like a stretch but I have read they have been damged .

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May 4th, 2015, 12:01 PM   #16  
Be sure to answer my first post. I wanted to add to Weos comments. And I also don't want to give you false hope but its important NOT TO OVERLOOK anything, before diving in. The pump is bullet proof as Weos stated but it has been known to fail. It has a enternal by-pass. The by-pass opens up on (spring pressure and small piton) rise in pressure and the oil just stays inside the pump. When I had my oil pressure problem I ran across this guys post. He came back and even posted a video about it. If you search you can find it. The piston had a burr on it and got wedged in the by-pass mode. I thought that was interesting.

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April 7th, 2016, 12:52 PM   #17  
i had a problem on a 2003 6.0 changed the senor then replaced the gauge in the cluster then bought a mechanical gauge tester from gearwrench pressure was 40 , truck had a fram filter replaced with a nappa stays at 30-35 i'm happy

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May 22nd, 2016, 7:30 PM   #18  
Low oil pressure

Before you replace that oil pump try replacing the oil pickup tube o-ring. I have a 2005 Avalanche with 200000 miles within the last 2000 miles the valve train was noisy at startup and an intermittent lifter tap. After many hours on the internet I decided to take a chance and drop the oil pan and replace the oil tube pickup o-ring. When I disconnected the pickup tube the o-ring dropped and was in three pieces. After replacing the o-ring oil pressure increased 20 psi and no valve train noise even at cold startup. If I were you I would try changing the O-ring first before you spend any money on a new oil pump. The problem with changing the oil pump first is there going to change .
o-ring when they change the oil pump and then your oil pressure will be perfect again but it might have been just the O-ring and not the pump

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