Recent Topics
ECOGARD X4612 NEW FILTER CUT OPEN
by 53' Stude. 07/20/19 06:48 PM
Show me your dinner
by 53' Stude. 07/20/19 05:52 PM
Shelf life of Gumout fuel injector cleaner
by pentode. 07/20/19 05:24 PM
Started a big job on the Carrera
by rooflessVW. 07/20/19 05:17 PM
Taco Bell Cantina
by vavavroom. 07/20/19 05:13 PM
TEC SELECT T 4612 CUT OPEN
by 53' Stude. 07/20/19 05:01 PM
2012 Ford 3.0 V6 Kendall GT-1 5W-20 6488 mi
by AITG. 07/20/19 04:37 PM
Replaced All Signaling Bulbs At One Time
by RayCJ. 07/20/19 04:21 PM
Cheryl's New She Shed
by MolaKule. 07/20/19 04:16 PM
Thread sealant for bolts holding diff cover.
by Snagglefoot. 07/20/19 03:30 PM
Meguiars Hybrid Ceramic
by rdevans89. 07/20/19 03:02 PM
2015 Mitsubishi Outlander GT trans. filter
by Kira. 07/20/19 03:02 PM
Could microglass/synthetic media filters harm engines?
by Deontologist. 07/20/19 01:47 PM
A/C problems 2016 Nissan Quest.
by JTK. 07/20/19 01:37 PM
change once a year regimen
by alex_at. 07/20/19 01:34 PM
What would you like to do in the future?
by Red91. 07/20/19 12:45 PM
Pulling timing for high IAT
by LAGA. 07/20/19 11:55 AM
I think I messed up. How badly?
by JohnG. 07/20/19 11:19 AM
Newest Members
Roadtripp, Denali376, GoldDot40, Dtn2, Bonebender
68717 Registered Users
Who's Online Now
96 registered members (Ammofirst, 53' Stude, AdditiveOCD, AlienBug, 01rangerxl, 10 invisible), 2,071 guests, and 29 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics292,159
Posts5,017,829
Members68,717
Most Online2,967
Mar 10th, 2019
Donate to BITOG
Hop To
Page 1 of 2 1 2
5w20 + 5w40 = 10w30? #5125914
06/05/19 12:45 PM
06/05/19 12:45 PM
Joined: Aug 2002
Posts: 15,264
Silicon Valley
PandaBear Offline OP
PandaBear  Offline OP

Joined: Aug 2002
Posts: 15,264
Silicon Valley
Reason for asking: Scored some $10.97 Valvoline MST 5w40 recently, had a bunch of 5w20 Valvoline Synthetic from last year's discount. Based on data sheet it seems like they are 66cst/13cst and 44cst/8cst. So if I mix them 1:1, am I correct that it should come out to around 50cst/10cst? In that case it should be a Xw30 oil for cheap.

Would that make sense? Anything I'm missing? It would be for a warm climate car (90F in the summer high and 45F in the winter low).


"You keep asking questions PandaBear and you'll end up a vegetarian like my wife" - Camu Mahubah
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125917
06/05/19 12:50 PM
06/05/19 12:50 PM
Joined: Apr 2016
Posts: 339
Florida
1978elcamino Offline
1978elcamino  Offline

Joined: Apr 2016
Posts: 339
Florida
Actually, that would be 5w30, however the add pack between the two blends will be different. I would recommend running the 40 in the warmer months and the 20 during the cooler months and not mix them. Just my .02


2018 F150 5.0
2016 Ford Fusion 2.5
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125923
06/05/19 12:58 PM
06/05/19 12:58 PM
Joined: Dec 2005
Posts: 11,712
Upper Midwest
kschachn Online content
kschachn  Online Content

Joined: Dec 2005
Posts: 11,712
Upper Midwest
Yes, it will probably be a 5W but there is no guarantee, just as there is no guarantee it will meet any of the approvals or certifications listed on either container. It will be a safe mixture however since ASTM D6922 provides for miscibility.


1994 BMW 530i, 242K
1996 Honda Accord, 277K
1999 Toyota Sienna, 418K
2000 Toyota ECHO, 281K
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125927
06/05/19 01:06 PM
06/05/19 01:06 PM
Joined: May 2019
Posts: 765
WA
Mad_Hatter Offline
Mad_Hatter  Offline

Joined: May 2019
Posts: 765
WA
I've been wondering about that question.. how to figure out a frankenmix. That said, I don't see how adding a 5w to a 5w gets you a 10wX???

Re: 5w20 + 5w40 = 10w30? [Re: Mad_Hatter] #5125929
06/05/19 01:08 PM
06/05/19 01:08 PM
Joined: Apr 2008
Posts: 40,167
Ontario, Canada
OVERKILL Offline
OVERKILL  Offline

Joined: Apr 2008
Posts: 40,167
Ontario, Canada
Originally Posted by Mad_Hatter
I've been wondering about that question.. how to figure out a frankenmix. That said, I don't see how adding a 5w to a 5w gets you a 10wX???


PPD's and base oil blends. What base in oil 1 might require x amount of PPD's may not remain the same for oil 2, so you end up with insufficient PPD for the end blend to meet the W rating that either of the independent constituents held.


2019 RAM 1500 Sport - Mobil 1 EP 0w-20, FRAM Ultra
2016 Grand Cherokee SRT - Ravenol SSL 0w-40, FRAM Ultra
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125941
06/05/19 01:16 PM
06/05/19 01:16 PM
Joined: Aug 2002
Posts: 15,264
Silicon Valley
PandaBear Offline OP
PandaBear  Offline OP

Joined: Aug 2002
Posts: 15,264
Silicon Valley
How different are the additives between 5w40 MST vs 5w20 "Advanced Full Synthetic"?


"You keep asking questions PandaBear and you'll end up a vegetarian like my wife" - Camu Mahubah
Re: 5w20 + 5w40 = 10w30? [Re: OVERKILL] #5125943
06/05/19 01:17 PM
06/05/19 01:17 PM
Joined: May 2019
Posts: 765
WA
Mad_Hatter Offline
Mad_Hatter  Offline

Joined: May 2019
Posts: 765
WA
Originally Posted by OVERKILL
Originally Posted by Mad_Hatter
I've been wondering about that question.. how to figure out a frankenmix. That said, I don't see how adding a 5w to a 5w gets you a 10wX???


PPD's and base oil blends. What base in oil 1 might require x amount of PPD's may not remain the same for oil 2, so you end up with insufficient PPD for the end blend to meet the W rating that either of the independent constituents held.


Got it... So if I understand that right, in practice there's no real way to know what the end result is without testing it but as a rule of thumb it's going to be lower than each constituent or as low as the lowest constituent oil???

Does it have that same effect on the upper viscosity rating also? (for both the low and the high of a multi vis?)

Last edited by Mad_Hatter; 06/05/19 01:26 PM.
Re: 5w20 + 5w40 = 10w30? [Re: Mad_Hatter] #5125951
06/05/19 01:26 PM
06/05/19 01:26 PM
Joined: Apr 2008
Posts: 40,167
Ontario, Canada
OVERKILL Offline
OVERKILL  Offline

Joined: Apr 2008
Posts: 40,167
Ontario, Canada
Originally Posted by Mad_Hatter
Originally Posted by OVERKILL
Originally Posted by Mad_Hatter
I've been wondering about that question.. how to figure out a frankenmix. That said, I don't see how adding a 5w to a 5w gets you a 10wX???


PPD's and base oil blends. What base in oil 1 might require x amount of PPD's may not remain the same for oil 2, so you end up with insufficient PPD for the end blend to meet the W rating that either of the independent constituents held.


Got it... So if I understand that right, in practice there's no real way to know what the end result is without testing it but as a rule of thumb it's going to be lower than each constituent???

Does it have that same effect on the upper viscosity rating also? (for both the low and the high of a multi vis?)


Correct.

The impact on the hot side of things is much more predictable, as you are primarily just dealing with VII's. It's the cold side of things where you dealing with trying to mitigate wax crystal formation that things get more difficult, as different bases can have wildly different cold temperature behaviours.


2019 RAM 1500 Sport - Mobil 1 EP 0w-20, FRAM Ultra
2016 Grand Cherokee SRT - Ravenol SSL 0w-40, FRAM Ultra
Re: 5w20 + 5w40 = 10w30? [Re: OVERKILL] #5125958
06/05/19 01:30 PM
06/05/19 01:30 PM
Joined: May 2019
Posts: 765
WA
Mad_Hatter Offline
Mad_Hatter  Offline

Joined: May 2019
Posts: 765
WA
Originally Posted by OVERKILL
Originally Posted by Mad_Hatter
Originally Posted by OVERKILL
Originally Posted by Mad_Hatter
I've been wondering about that question.. how to figure out a frankenmix. That said, I don't see how adding a 5w to a 5w gets you a 10wX???


PPD's and base oil blends. What base in oil 1 might require x amount of PPD's may not remain the same for oil 2, so you end up with insufficient PPD for the end blend to meet the W rating that either of the independent constituents held.


Got it... So if I understand that right, in practice there's no real way to know what the end result is without testing it but as a rule of thumb it's going to be lower than each constituent???

Does it have that same effect on the upper viscosity rating also? (for both the low and the high of a multi vis?)


Correct.

The impact on the hot side of things is much more predictable, as you are primarily just dealing with VII's. It's the cold side of things where you dealing with trying to mitigate wax crystal formation that things get more difficult, as different bases can have wildly different cold temperature behaviours.


Makes sense...tx👍

Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125962
06/05/19 01:31 PM
06/05/19 01:31 PM
Joined: Apr 2008
Posts: 40,167
Ontario, Canada
OVERKILL Offline
OVERKILL  Offline

Joined: Apr 2008
Posts: 40,167
Ontario, Canada
You are quite welcome.


2019 RAM 1500 Sport - Mobil 1 EP 0w-20, FRAM Ultra
2016 Grand Cherokee SRT - Ravenol SSL 0w-40, FRAM Ultra
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5125968
06/05/19 01:33 PM
06/05/19 01:33 PM
Joined: Aug 2017
Posts: 294
CA
ad244 Offline
ad244  Offline

Joined: Aug 2017
Posts: 294
CA
What vehicle is it going in?

Re: 5w20 + 5w40 = 10w30? [Re: ad244] #5125972
06/05/19 01:34 PM
06/05/19 01:34 PM
Joined: Aug 2002
Posts: 15,264
Silicon Valley
PandaBear Offline OP
PandaBear  Offline OP

Joined: Aug 2002
Posts: 15,264
Silicon Valley
Originally Posted by ad244
What vehicle is it going in?


Haven't decided yet, either 08 IS250 or 97 Integra.


"You keep asking questions PandaBear and you'll end up a vegetarian like my wife" - Camu Mahubah
Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5126033
06/05/19 02:34 PM
06/05/19 02:34 PM
Joined: Sep 2007
Posts: 1,235
TX, USA
JMJNet Offline
JMJNet  Offline

Joined: Sep 2007
Posts: 1,235
TX, USA
It is NOT linearly additive. So it is not as straight forward by simply averaging the values.
It is probably closer to the 5w-30, though.

IIRC, there is a calculator here somewhere at BITOG.


  • 2017 Toyota Sienna
  • 1995 GMC Suburban 6.5L Turbo Diesel


Re: 5w20 + 5w40 = 10w30? [Re: JMJNet] #5126036
06/05/19 02:35 PM
06/05/19 02:35 PM
Joined: May 2019
Posts: 765
WA
Mad_Hatter Offline
Mad_Hatter  Offline

Joined: May 2019
Posts: 765
WA
Originally Posted by JMJNet
It is NOT linearly additive. So it is not as straight forward by simply averaging the values.
It is probably closer to the 5w-30, though.

IIRC, there is a calculator here somewhere at BITOG.


Now that would be neat/useful...👍

Re: 5w20 + 5w40 = 10w30? [Re: PandaBear] #5126045
06/05/19 02:39 PM
06/05/19 02:39 PM
Joined: Apr 2004
Posts: 925
Indiana
nascarnation Offline
nascarnation  Offline

Joined: Apr 2004
Posts: 925
Indiana
I certainly wouldn't worry about this mixture of two known good oils.
I've run Mobil 0W40 mixed with MileSyn 0W20 in my Caddy V6 (specc'd for 5W30) and it hasn't blown up yet.

Page 1 of 2 1 2
Previous Thread
Index
Next Thread

BOB IS THE OIL GUY® Powered by UBB.threads™