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Oil viscosity questions #4588463
11/29/17 08:42 AM
11/29/17 08:42 AM
Joined: Nov 2017
Posts: 91
SC, USA
Bxnanaz Offline OP
Bxnanaz  Offline OP
Joined: Nov 2017
Posts: 91
SC, USA
Hello BITOGers! Long time lurker, new member.
So I’ve been wondering for a while but haven’t found a good answer. Many people believe that “thicker” viscosity oils protect better. Well with most if not all engines having an oil pump pressure relief valve, wouldn’t the best oil viscosity be as thin as possible to yet still hit that relieve valve pressure spec when hot?

Example: my 2017 Silverado calls for 0W-20. It has a relief valve pressure spec of ~40 until 3500rpm, when it then hits a second stage of flow where it ramps up 60+. I frequently tow 5K+ LBs in the hot summer months and it pretty much always hits that ~40 psi spec before 3500 rpm. In my mind, this is a good viscosity for this engine. What’re yalls thoughts?

Re: Oil viscosity questions [Re: Bxnanaz] #4588471
11/29/17 08:47 AM
11/29/17 08:47 AM
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
StevieC Online content
StevieC  Online Content
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
welcome to BITOG!

The engineers know best. Whatever your manual calls for in the temperature it will be operated under the service category (Regular, Heavy Duty etc.) is what you should use.

That said a quality 0w20 if that is what the manual calls for, is suitable. You can verify this with a UOA to be sure! thumbsup

FWIW there are others on here with Ram trucks doing towing with 20wts in the crank case. wink

Last edited by StevieC; 11/29/17 08:50 AM.

'18 Highlander - AMSOIL SS 0w20 / ATF / Severe Gear
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF (R.I.P)
Re: Oil viscosity questions [Re: Bxnanaz] #4588478
11/29/17 08:55 AM
11/29/17 08:55 AM
Joined: Sep 2015
Posts: 2,256
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,256
Malaysia
Oil pump relief valve pressure is never a parameter in determining suitable oil grade use or lubricant performance.
It's about engine system protection , say preventing filter bursting.

Re: Oil viscosity questions [Re: StevieC] #4588492
11/29/17 09:03 AM
11/29/17 09:03 AM
Joined: Nov 2017
Posts: 91
SC, USA
Bxnanaz Offline OP
Bxnanaz  Offline OP
Joined: Nov 2017
Posts: 91
SC, USA
Originally Posted By: StevieC
welcome to BITOG!

The engineers know best. Whatever your manual calls for in the temperature it will be operated under the service category (Regular, Heavy Duty etc.) is what you should use.

That said a quality 0w20 if that is what the manual calls for, is suitable. You can verify this with a UOA to be sure! thumbsup

FWIW there are others on here with Ram trucks doing towing with 20wts in the crank case. wink




Thanks for the response! I have no doubt 20wts can protect my engine more than adequately. Not saying I would trust them for long drain intervals though. I’ve been running about 4,000 mile intervals with 0w-20 M1 AFE. I know it’s probably way too short, but probably 50% or more of those miles are towing miles so I figured might as well be safe. Will do a UOA now that I have about 13k on the truck and have performed my 4th change. (One of which was at 500 miles).

Switched over to Penzoil Platinum seeing as it was on sale and my engine is actually noticeably quieter at idle. Had the ever so slightest tick on M1 that I attributed to DI noises.

Re: Oil viscosity questions [Re: Bxnanaz] #4588512
11/29/17 09:28 AM
11/29/17 09:28 AM
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
StevieC Online content
StevieC  Online Content
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
I would recommend using Test Oil's Ohio lab because I know their calibration is top rate.


'18 Highlander - AMSOIL SS 0w20 / ATF / Severe Gear
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF (R.I.P)
Re: Oil viscosity questions [Re: Bxnanaz] #4588517
11/29/17 09:30 AM
11/29/17 09:30 AM
Joined: Dec 2005
Posts: 9,862
Upper Midwest
kschachn Offline
kschachn  Offline
Joined: Dec 2005
Posts: 9,862
Upper Midwest
Originally Posted By: Bxnanaz
Thanks for the response! I have no doubt 20wts can protect my engine more than adequately. Not saying I would trust them for long drain intervals though. I’ve been running about 4,000 mile intervals with 0w-20 M1 AFE. I know it’s probably way too short, but probably 50% or more of those miles are towing miles so I figured might as well be safe. Will do a UOA now that I have about 13k on the truck and have performed my 4th change. (One of which was at 500 miles).

The safety of a long drain interval isn't really related to the grade. That wouldn't be my concern.


1994 BMW 530i, 228K
1996 Honda Accord, 263K
1999 Toyota Sienna, 400K
2000 Toyota ECHO, 271K
Re: Oil viscosity questions [Re: Bxnanaz] #4588534
11/29/17 09:52 AM
11/29/17 09:52 AM
Joined: May 2009
Posts: 12,180
N.H, U.S.A.
ARCOgraphite Offline
ARCOgraphite  Offline
Joined: May 2009
Posts: 12,180
N.H, U.S.A.
Forget UOA. If you want a little more high load safety margin (I don't know what you mean by protection) substitute a qt or 2 on the next oil change with a 30 grade.

Oil pressure just puts oil into the bearings the pressure doesn't float the shaft, that's the inherent working viscosity of the fluid. So Oil grade e.g: 20, 30, 40 provides your loading safety margin.

BTW, There is no 20wt or 30wt or "weight". Its a misuse of terminology.


2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter
Re: Oil viscosity questions [Re: Bxnanaz] #4588538
11/29/17 09:57 AM
11/29/17 09:57 AM
Joined: Oct 2015
Posts: 2,649
Balearic Islands , Spain
FordCapriDriver Offline
FordCapriDriver  Offline
Joined: Oct 2015
Posts: 2,649
Balearic Islands , Spain
It specs 0W-20 mainly because of fuel economy regulations.
If you use 0W-30, 5W-30 absolutely nothing bad will happen, 0W-20 will be fine though aswell, and personally until the warranty runs out i would run 0W-20, because that way if anything went wrong with the engine and they saw you didn't use their specified oil, that may void the warranty.


1975 Ford Capri II Ghia 3000 V6, - Shell Helix HX3 20W-50 w/ 20% Rimula R4X 15W-40 HDEO.

1988 Ford Escort Mk4 Xr3i Cabrio, - Shell Rimula R4X 15W-40, w/ 30% Helix 3 20W-50.
Re: Oil viscosity questions [Re: FordCapriDriver] #4588663
11/29/17 11:55 AM
11/29/17 11:55 AM
Joined: Nov 2017
Posts: 91
SC, USA
Bxnanaz Offline OP
Bxnanaz  Offline OP
Joined: Nov 2017
Posts: 91
SC, USA
Originally Posted By: FordCapriDriver
It specs 0W-20 mainly because of fuel economy regulations.
If you use 0W-30, 5W-30 absolutely nothing bad will happen, 0W-20 will be fine though aswell, and personally until the warranty runs out i would run 0W-20, because that way if anything went wrong with the engine and they saw you didn't use their specified oil, that may void the warranty.


Warranty is the main reason I’m gonna keep running 0w-20. UOAs will help me determine what I run after warranty

Re: Oil viscosity questions [Re: zeng] #4588728
11/29/17 12:39 PM
11/29/17 12:39 PM
Joined: Dec 2016
Posts: 6,226
Waco, TX
Linctex Offline
Linctex  Offline
Joined: Dec 2016
Posts: 6,226
Waco, TX
Originally Posted By: zeng
Oil pump relief valve pressure is never a parameter in determining suitable oil grade use or lubricant performance.


Correct.

Hydrodynamic protection between two metal surfaces is the REAL criteria.

Metal making contact with metal = no bueno


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: Oil viscosity questions [Re: Bxnanaz] #4588738
11/29/17 12:49 PM
11/29/17 12:49 PM
Joined: Nov 2017
Posts: 91
SC, USA
Bxnanaz Offline OP
Bxnanaz  Offline OP
Joined: Nov 2017
Posts: 91
SC, USA
My thought process was if the relief valve is set a X pressure, and a 0W-20 hits X pressure, why go any “thicker”.? Obviously I was wrong on that.

Re: Oil viscosity questions [Re: Bxnanaz] #4588750
11/29/17 12:59 PM
11/29/17 12:59 PM
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
StevieC Online content
StevieC  Online Content
Joined: Aug 2008
Posts: 18,287
Ontario, Canada
Pressure doesn't equate with protection. Flow has more to do with it. That's not to say you don't need some pressure but it's not the be all end all.


'18 Highlander - AMSOIL SS 0w20 / ATF / Severe Gear
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF (R.I.P)
Re: Oil viscosity questions [Re: Bxnanaz] #4588753
11/29/17 12:59 PM
11/29/17 12:59 PM
Joined: May 2009
Posts: 12,180
N.H, U.S.A.
ARCOgraphite Offline
ARCOgraphite  Offline
Joined: May 2009
Posts: 12,180
N.H, U.S.A.
Don't! UOA is junk science.

Throw some ten dubbya thirty in there b4 its too late, pardner.

Like I say maybe 1 or 2 qts of the mix.

Dealer doesn't have a clue what oil is in there. And 1-2 cst gooey-er oil isn't going to ding ANY alarms.

Don be a fairy trucker 'fraid of the big bad mean dealer. I'm shaken in my boots!

You motor would be proud to be in a Z28 or Vette in the 70's as a High Output option. It putting down some powah! It neeeeds some vis coz city!

Yeah, good luck on that 20 grade. He He.


2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter
Re: Oil viscosity questions [Re: Bxnanaz] #4588763
11/29/17 01:07 PM
11/29/17 01:07 PM
Joined: Sep 2010
Posts: 6,986
Texas
4WD Offline
4WD  Offline
Joined: Sep 2010
Posts: 6,986
Texas
My thoughts are I have that motor and the 0w20 bugs me a bit … the 8 quarts gives me mixed emotions … might hold up to DI better than 6 quarts ~ but 6 quarts of 5w30 is pretty cheap and good for south Texas use …

Re: Oil viscosity questions [Re: StevieC] #4588843
11/29/17 02:00 PM
11/29/17 02:00 PM
Joined: Dec 2005
Posts: 9,862
Upper Midwest
kschachn Offline
kschachn  Offline
Joined: Dec 2005
Posts: 9,862
Upper Midwest
Originally Posted By: StevieC
Pressure doesn't equate with protection. Flow has more to do with it. That's not to say you don't need some pressure but it's not the be all end all.

Please explain? In a technical way I mean.


1994 BMW 530i, 228K
1996 Honda Accord, 263K
1999 Toyota Sienna, 400K
2000 Toyota ECHO, 271K
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