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LML Oil Pressure Variance??? #4528146
09/28/17 06:29 AM
09/28/17 06:29 AM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
I did my 3rd oil change since 14k miles using Amsoil 15w40 Signature Series and EAO52 filter so far just using the oil life monitoring system. The oil pressure has been consistent 21psi hot idle and 40psi cruising at 60mph. I've had I bought the truck with 9k miles and first change the oil to Rotella T6 and Mobil 1 oil filter with same oil pressure results using my CTS2 monitor. The other night I changed my oil for the 3rd time using Amsoil and notice now oil pressure at 22psi hot idle and 45psi cruising on the highway also the truck feels to have an increase in power. So why would my oil pressure be higher now on the 4th oil change? I switched to Amsoil because I wasn't happy with the Rotella T6 I noticed a little oil coming from my exhaust and a puff of white smoke on startup but haven't experienced any of this with the Amsoil. Did I get a bad filter or possibly the the engine is broke in now with 33k on it. I also noticed my operating temp is a couple degrees lower too now.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528213
09/28/17 08:27 AM
09/28/17 08:27 AM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
The truck is a 2016 6.6 Duramax.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528214
09/28/17 08:27 AM
09/28/17 08:27 AM
Joined: Nov 2009
Posts: 4,943
Houston, Texas
motor_oil_madman Offline
motor_oil_madman  Offline
Joined: Nov 2009
Posts: 4,943
Houston, Texas
It's colder outside now.


2007.5 dodge cummins 6.7 liter. Chevron Delo400 15w40. 7000 mile or 250-300hr intervals.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528217
09/28/17 08:28 AM
09/28/17 08:28 AM
Joined: Nov 2009
Posts: 4,943
Houston, Texas
motor_oil_madman Offline
motor_oil_madman  Offline
Joined: Nov 2009
Posts: 4,943
Houston, Texas
Oil will be a bit thinner when it is 100 outside vs 80 degrees


2007.5 dodge cummins 6.7 liter. Chevron Delo400 15w40. 7000 mile or 250-300hr intervals.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528282
09/28/17 09:48 AM
09/28/17 09:48 AM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
I 100% agree but the temp just dropped a little this morning. We had the same temperature drop on the last oil change and it was ineffective. I'm just curious how do you know if your oil filter is in bypass or even bad?

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528335
09/28/17 10:41 AM
09/28/17 10:41 AM
Joined: Sep 2015
Posts: 5,868
Kalifornia Kollective
BrocLuno Offline
BrocLuno  Offline
Joined: Sep 2015
Posts: 5,868
Kalifornia Kollective
Oil filter by-pass's internally when media won't flow the volume being pumped. Two ways to play this game. Filter with higher internal by-pass built-in, or bigger filter with more media area so it never sees enough restriction to cold oil to open the by-pass in the first place smile


Formerly in marine engineering. In an earlier life I owned my own petroleum tank truck, and hauled for the majors and independent's.
Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528412
09/28/17 12:26 PM
09/28/17 12:26 PM
Joined: May 2007
Posts: 7,509
Indianapolis, IN
dnewton3 Offline
dnewton3  Offline
Joined: May 2007
Posts: 7,509
Indianapolis, IN
Totally coincidental. Oil pressures will always vary a bit. The oil will only be "thinner" when it's cooler outside because it will take a little bit longer to warm up. Once up to full op temp it will be controlled by the oil cooler which uses the engine coolant to control temps.

Also, oIl filters rarely ever go into BP, and when they do, it's only for a VERY short time (less than a few seconds) at cold start up. Once the oil pressure comes up in the full system, the dP across the filter is far less than the overall operating pressure, and never close to the filter BP crack-open. This has been proven (data logging experiments from Jim Allen) elsewhere on this site. Typically oil filters can flow WAY more than the engine will pump, as a safety design feature so as to not induce a media rupture.


What I don't understand is why folks worry about this stuff; it's minutia and is no indication of anything going right or wrong.


The act of preventative maintenance, in and of itself, is FAR MORE important than brand/grade/base choices among lubes and filters.
- under maintaining something is akin to abuse/neglect; that can kill equipment by shortening the lifespan
- over maintaining something has never been proven to be anything but a waste of time and money
Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528456
09/28/17 01:15 PM
09/28/17 01:15 PM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
Dnewton I wasn't necessarily worried as much I was curious? I was wondering if there was a difference in the oil enough to bring a 5 psi difference driving 60 or mabey even an issue or difference in the filters?

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4528733
09/28/17 07:18 PM
09/28/17 07:18 PM
Joined: May 2007
Posts: 7,509
Indianapolis, IN
dnewton3 Offline
dnewton3  Offline
Joined: May 2007
Posts: 7,509
Indianapolis, IN
No problem. It's really just too hard to compare/contrast such small nuances without understanding all the variables.

As a fellow Dmax owner, the wear rates are so low and consistence, I guess curiosity about oil pressure is about all we have to talk about!

And unless you're running extended OCIs, just ditch the syns; big waste of money.
The Dmax is the best wearing light-duty diesel engine in modern times. Simply impeccable wear traits. Using a syn does nothing to improve the already great wear rates.

Last edited by dnewton3; 09/28/17 07:20 PM.

The act of preventative maintenance, in and of itself, is FAR MORE important than brand/grade/base choices among lubes and filters.
- under maintaining something is akin to abuse/neglect; that can kill equipment by shortening the lifespan
- over maintaining something has never been proven to be anything but a waste of time and money
Re: LML Oil Pressure Variance??? [Re: redneck47441] #4549791
10/21/17 12:29 AM
10/21/17 12:29 AM
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
Hasty66 Offline
Hasty66  Offline
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
I have a 2013 Duramax and have the EZ Lynk setup. Warmed up here in Texas my pressure will run around 22 psi at idle and 44 driving. First start up in the morning the pressure at idle can be as high as 62 psi. I'm currently at 53K miles and I use Mobil Delvac 15w-40 I buy at Wally World.


2013 Chevy Silverado 2500HD LTZ CC/SB 4x4 Duramax
2013 Jeep Grand Cherokee Overland 5.7L
2005 Ford F-150 Lariat CC/SB 4x4 5.4L
Re: LML Oil Pressure Variance??? [Re: redneck47441] #4550170
10/21/17 12:40 PM
10/21/17 12:40 PM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
Hasty what I was getting at is my oil pressure was higher for the first few hundred miles after an oil change then the average dropped a bit with no difference in outside temperatures.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4550669
10/22/17 01:18 AM
10/22/17 01:18 AM
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
Hasty66 Offline
Hasty66  Offline
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
I can't say the same with mine, it is pretty consistent from fill to drain with Mobil Delvac or Amsoil.

Last edited by Hasty66; 10/22/17 01:22 AM.

2013 Chevy Silverado 2500HD LTZ CC/SB 4x4 Duramax
2013 Jeep Grand Cherokee Overland 5.7L
2005 Ford F-150 Lariat CC/SB 4x4 5.4L
Re: LML Oil Pressure Variance??? [Re: redneck47441] #4551423
10/22/17 08:42 PM
10/22/17 08:42 PM
Joined: Mar 2015
Posts: 27
Indiana
redneck47441 Offline OP
redneck47441  Offline OP
Joined: Mar 2015
Posts: 27
Indiana
Hasty your saying its the same with Mobil Delvac conventional 15w40 and Amsoil 15w40? If so are you also running the Amsoil filter? This last change I did 1500 miles ago with conventional 15w40 and donaldson filter and my pressure has been the same so far.

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4553452
10/24/17 07:20 PM
10/24/17 07:20 PM
Joined: Aug 2010
Posts: 1,025
pa
benjy Offline
benjy  Offline
Joined: Aug 2010
Posts: 1,025
pa
oil viscosities are spec'd @ 40C + 100C + vary from there. base oils that are real synthetic-group IV + V which there are few will thicken less + slower under the 40C spec + they will thin less over the 100C spec. this could effect oil pressures both warm + cold!!

Re: LML Oil Pressure Variance??? [Re: redneck47441] #4571850
11/12/17 02:59 PM
11/12/17 02:59 PM
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
Hasty66 Offline
Hasty66  Offline
Joined: Sep 2017
Posts: 13
San Antonio & Houston, Texas
Never used an Amsoil filter, I use M1-303 or B1441. I have run both filters with Mobil Delvac conventional 15w40 and Amsoil 15w40 OE/Heavy Duty oils. Temperature stays warm to HOT in this part of the country so not much experience beyond a very rare 32 and below start up when my pressure will jump up to 79-80 then drop down to normal once the oil is warmed up.

I have never noticed the slight difference after a change like you have noted.


2013 Chevy Silverado 2500HD LTZ CC/SB 4x4 Duramax
2013 Jeep Grand Cherokee Overland 5.7L
2005 Ford F-150 Lariat CC/SB 4x4 5.4L
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