# Duramax low oil pressure??



## MuskokaDon (Nov 28, 2007)

Hey guys/gals

Not sure if i have a problem or not... 

i have an 04.5 duramax and i notice low oil pressure when driving and not on the pedel
(almost on the red line low) it has always been like this. It sits at around 400 on the gauge when at wot.
Reason i ask is i was in a friends d-max the other day and his pressure is much higher.
Now i am running synthetic (not sure on the weight) could this be the reason for the low pressure or could i have a problem??


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## brad96z28 (Aug 21, 2005)

I wish I could be a little more help I have the same truck lly. But recently my oil pressure gauge stopped working. they did have a lot of cluster problems but It would always be best to ck the oil pressure with a mechanical gauge. I going to take apart my cluster and change out the stepper motor and see what my gauge at idle is I run the synthetic 5w 40 in the winter as well.


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## MuskokaDon (Nov 28, 2007)

so you think it could just be my gauge?


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## brad96z28 (Aug 21, 2005)

Without cking ur pressure with a mechanical gauge . I can only assume. But if I remember correctly When hot mine read around 20 psi at idle and it changed dramaticly just off idle. I have read that most of these do that and are normal. But I will see If i can find out more info for u.


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## brad96z28 (Aug 21, 2005)

Ok I had found where I had read about outher peope having questionable oil pressures. If u want to read about them. http://www.dieselbombers.com/chevy-gmc-duramax-04-5-05-lly/14558-oil-pressure.html and http://www.dieselplace.com/forum/showthread.php?p=2881344#post2881344


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## MuskokaDon (Nov 28, 2007)

Thanks Brad.. i feel much better now. Looks like it's normal on the newer max's. Thank you for tracking that down! :salute:


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## brad96z28 (Aug 21, 2005)

MuskokaDon;675019 said:


> Thanks Brad.. i feel much better now. Looks like it's normal on the newer max's. Thank you for tracking that down! :salute:


No problem I may have been able to tell u mine was the same if my gauge was actually functional:realmad: Keep up with those great vids:salute:


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## Spitz (Feb 28, 2008)

I know gas engines usually 10psi to every 1000rpm is a good rule of thumb. Although many require as little as 5-6psi at 1000 which doesnt seem like much at all. I would think a diesel would need a little more.. Also i recall a TSB about oil pressure on some of the durmaxes. The tsb refered to the "low oil pressure" message in the driver message center.


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## tuney443 (Jun 25, 2006)

MuskokaDon;674656 said:


> Hey guys/gals
> 
> Not sure if i have a problem or not...
> 
> ...


Having trouble understanding you.Do you mean 40 PSI at wide open throttle? If so,that is a little on the low side but it doesn't necessarily mean you have a problem.I run Schaeffer 15/40 dino oil--at 2K RPM,I'm at app.60PSI,of course that's at operating temp.If you're running a 5/40 synthetic,that might explain your low pressure.Why don't you know what oil you're running though?


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## MuskokaDon (Nov 28, 2007)

tuney443;675231 said:


> Having trouble understanding you.Do you mean 40 PSI at wide open throttle? If so,that is a little on the low side but it doesn't necessarily mean you have a problem.I run Schaeffer 15/40 dino oil--at 2K RPM,I'm at app.60PSI,of course that's at operating temp.If you're running a 5/40 synthetic,that might explain your low pressure.Why don't you know what oil you're running though?


It's a Canadian truck, so the gauge is in kpa not psi.. 
When the truck is warm running down the road with no throttle it almost hit the red line.. at wot it reads just under 400.
I just now went outside, started the truck and took this pic so you can see what the gauge looks like...and as you can see it has lots of pressure. keep in mind the truck has not run in 24hrs and it is -3 outside atm.


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## tuney443 (Jun 25, 2006)

OK,now I understand better.Usually when someone says redline,it's a reference to a high RPM on the tach,going into the red.So your oil is at it's thickest right now,it's real cold out,and your PSI,sorry,KPA is completely normal, which leads me to believe you have a very light weight {2nd # of the viscosity} oil.Add this to it's being synthetic,which is thinner than dino oil,relatively speaking,so it's important that you find out what weight oil you've got.


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## brad96z28 (Aug 21, 2005)

http://www.csgnetwork.com/presskpapsicvt.html
400 kpa equil to 58 psi. Quite healty there. But I know the problem Is when warm at idle. And established that is a common concern that appears to be normal. One person said It has a low pressure high volume pump.I cant confirm that but I think its time to move on.


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## Spitz (Feb 28, 2008)

Why is synthetic oil thinner? Viscosity is viscosity, doesnt matter if its horse doo doo or oil. Like said im sure there is a TSB about this issue, heres one #04-06-04-001C. Really depends if your getting the "low oil pressure" message in the driver center, if not, dont worry about it, all pressure will drop when the engine is warm.. If your worried, have a tech install a manual gauge and drive it around for a while to get it hot, and that will show you exactly what pressure its at, not all guages and sending units are dead on accurate, some are actually quite a lot off. Some i've seen are +/- 10psi.


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## MuskokaDon (Nov 28, 2007)

I found out it has 5/40 synthetic in it..
I am comfortable with the fact that it's just the way they are... no issues

Thanks for all the help guys


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