There is very little force on the motor at idle so 9-12 psi isn't going to do too much damage.......the main issue is more what the psi was under load. If you manually hooked an analog pressure gauge to the oil sender port (this is a must do step so you know it's not an electrical issue with the sender) and got low readings on the highway then yes, it's probably not a bad idea to replace the pump if all else is working well. I wouldn't bother with a rebuild but the issue is that the motor will need to come out to change the pump. Good news is that this will let you pull the pan off and double check/clean any debris at the bottom of the oil pan.

Here's why the pan needs to come off (at right of crankshaft, you can see oil pump goes below the pan):

 

Is that 9-12 psi at idle? These motors are known to have low PSI at idle.

I've had the same issues. I replaced the OPS twice, and also a new pigtail connector. Mine at one point was dinging so much it was almost unbearable. After replacing the pigtail, it doesn't do it nearly as much as before, but randomly will. I just installed an EDGE CTS Monitor and ran diagnostics on it, pulled up trouble codes (no CEL) and I have a Oil Pressure Sensor low voltage. No other scanner has picked that up before. But reading my Oil Pressure on my CTS, its fine.

Before tearing into your engine, I'd suggest finding the whole wiring harness for the OPS and just replace it. Maybe you have bad wires somewhere.

Whats your psi driving? If your manual gauge is low while driving then you have bigger issues than wiring.

 

Is that 9-12 psi at idle? These motors are known to have low PSI at idle.

I've had the same issues. I replaced the OPS twice, and also a new pigtail connector. Mine at one point was dinging so much it was almost unbearable. After replacing the pigtail, it doesn't do it nearly as much as before, but randomly will. I just installed an EDGE CTS Monitor and ran diagnostics on it, pulled up trouble codes (no CEL) and I have a Oil Pressure Sensor low voltage. No other scanner has picked that up before. But reading my Oil Pressure on my CTS, its fine.

Before tearing into your engine, I'd suggest finding the whole wiring harness for the OPS and just replace it. Maybe you have bad wires somewhere.

Whats your psi driving? If your manual gauge is low while driving then you have bigger issues than wiring.

I have almost the identical problem, have you been able to find the OPS harness replacement?

 

It is 9 to 12 at idle warm and around 28 @1800 rpm. Is it worth pulling off front cover to cHeck if the but backed off? And can you without pulling the motor? Does The entire harness come from the dealer? I can trace it into the loom with the oil level sensor. Seems like it can't be that long. Mine is getting unbearable to listen to. As soon as motor gets to be around 170 degrees it dings on deceleration. Thanks again for the replys and pictures.

 

If those pressures were seen on an analog oil pressure gauge then it's not an electrical issue at all IMHO. Minimum operating specs are 14 psi @ idle and 42 psi @ 1800 rpm (engine at operating temp in both cases) so if you actually got those readings I would be getting ready to change out that oil pump soon. Make sure you're running 15W40 until you get it replaced too.

 

Trace the wires first, then dig into the engine if you don't find anything.

 

"The 2005 LLY minimum @ idle is 7psi and 28psi @ 1800 rpm. That explains why the low oil pressure chime comes on at 9psi and the red line on the gauge is at 7.5 psi."

Thats a quote out of the Low Oil Pressure sticky at the top on the LLY Threads...

 

Those must be the minimums for the gauge to ding at you because the published GM specs are a bit different.

Lubrication System

Oil Capacity - with Filter
10 qt

9.5 L

Oil Capacity - without Filter
9.2 qt

8.7 L

Oil Pressure - Minimum- Hot - at idle
98 KPa

14 psi

Oil Pressure - Minimum - 1800 RPM
294 KPa

42 psi

Oil Relief Valve Opening Pressure
441 KPa

64 psi

Piston Cooling Jet Valve Opening Pressure
196 KPa

29 psi

Oil Pump

Gear Shaft Outside Diameter - Drive - Service Limit
19.86 mm

0.7819 in

Gear Shaft Outside Diameter - Drive - Production Value
19.947-19.960 mm

0.7853-0.7858 in

Gear Shaft Outside Diameter - Driven - Service Limit
19.86 mm

0.7819 in

Gear Shaft Outside Diameter - Driven - Production Value
19.947-19.960 mm

0.7853-0.7858 in

Gear Shaft-to-Bushing - Service Limit Clearance
0.14 mm

0.0055 in

Gear-to-Cover Clearance - Drive/Driven - Service Limit
0.109 mm

0.0043 in

Gear-to-Cover Clearance - Drive/Driven - Production Value
0.064-0.109 mm

0.0025-0.0043 in

Gear-to-Housing Clearance - Drive/Driven - Service Limit
0.22 mm

0.0087 in

Gear-to-Housing Clearance - Drive/Driven - Production Value
0.125-0.221 mm

0.0049-0.0087 in

 

I read that. However I called the dealer and checked alldata at work and other threads here say 14 is minimum. I just am getting annoyed the alarm chimes. I tried turning the radio up but it it's not working. I guess I'll try pulling off the front cover to check the but and re check the pressure manually with a different gauge just to be sure. I just am dreading the time and cost if it is the pump. Crazy idea but is there anyway to add an external electric pump that would keep a constant psi of 15 or so just to help out? I've never heard it tried. Don't know if I am way off base here.

 

Short answer is no, there's is no shortcut to fixing it unless you just got bad readings the first time.

 

Did you get it fixed? My truck is doing the same, I also changed the sensors and pigtail. driving me nuts! mechanical gauge says I have good oil pressure...

 

Did anybody ever find/fix the problem to this?? I would really appreciate the help!!

 

I guess if was me, and oil psi looked good with a mechanical gauge I would prolly try to disable the chimer??
Do you have a cts? That can can monitor oil psi thru the obd ll port....it might just get the same readings as the dash tho...I'm not sure.

 

Actually I have not tried the mechanical gauge, but I called my local diesel shop to see what they say about it and they said they have had around 10 in the past few years and have not found a single result. He said to just use a mechanical gauge as well. They said they did not try looking at the electrical part of it though... but I mean something apparently this common must have been solved by somebody?! The closest I have come to seeing an actual fix is finding bad wiring

 

I'd hook up a mechanical gauge to confirm there isn't a mechanical oil psi problem.

What brand/wieght of oil are you using?

Just for reference my 250k mile lly at hot idle has 18psi, running 1800 rpm has 38 psi hot via a cts. I'm using 5w-40 mobil 1.

 

I was going to try that next if I couldn't get any other soultions. And I use rotella 15w 40

 

Your psi matches my buddies 05 lly but normally I was running 30 or just below at hot idle and I have 230k on it

 

30 psi at hot idle is crazy high psi for a lly....you sure about that?

 

Do you have any tuning on it? Or any kind of aftermarket accessories?
If so maybe that is goofing up the readings? I don't know if that's even possible...just throwing ideas at you...

 

The last guy had a bully dog on it but nothing is on it now. I'm going to hook it up to my buddies efi live and see what it reads on his computer as well though

 

Yes sir, that's usally what it'd stick around to before, maybe a little less but not much

 

It definitely wouldn't get low enough to set off the alarm and say low oil pressure constantly either

 

Also in the video, the truck was doing that all by itself moving the oil pressure!! I did not give it any throttle until I started to turn the wheel. That's not normal

 

My 2005 LLY is doing this as well, it's not consistent at all it chimes maybe 2-3 times a year, truck runs perfect has 245,500km and I'm using Amsoil 15w-40. Finding a fix would be great but no luck yet

 

Hey guys I was looking around and can't seem to find what I'm looking for so ima ask in here before i start a new thread in trying to put an oil cooler set up on my truck using the earls oil filter sandwich plate now I've read several people say that the -10an fittings wont flow enough I'm assuming its the gpm that it wont flow enough not the psi but my question is how much gpm does our stock oil pump put out at high rpm? I though that -10an would flow up to 15 gpm cause I'm having alot of trouble finding -12 an fittings and finding someone to drill and tap the earls plate to larger fittings. Also i read one guy on duranaxdiesel forum that built his on kit said he used 10an fittings with 8an cooler and hose and his was fine thanks guys!

 

Has anyone found a fix to this yet?

 

https://www.duramaxforum.com/forum/04-5-05-lly-duramax-powertrain/980919-25w-60-my-lly.html

So far.... so good.

 

2005 lly, 7-10 psi at idle, 23-28 psi at 2000 rpms, have been told by 4 different duramax techs, this was normal but only in the 2005, lly,, not sure why but its scary when toting 13,500 lbs of 5th wheel cross country. 224,000 miles truck seems to run great, wish i knew for sure,

 

I see about 21-22 at idle when warm. Driving I’m about 40-48. I got an edge insight and monitor it there. I also changed the ops and it was reading the same as the old one I took out. After that, I had the cluster rebuilt. No issues now going on 3 years

 

Has anyone had a bad oil pressure relief valve cause this issue?