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I'm confused about the "cold" oil viscosity rating #4537519
10/08/17 08:57 PM
10/08/17 08:57 PM
Joined: Jan 2014
Posts: 270
USA
Avery4 Offline OP
Avery4  Offline OP
Joined: Jan 2014
Posts: 270
USA
I am confused about why, for example, a 30w oil is available when a 10w30 or 5w30 would apparently work just as well when hot and work much better while cold. Would there be a disadvantage to using 0w30 in hot weather instead of SAE 30?

Last edited by Avery4; 10/08/17 09:00 PM.
Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537522
10/08/17 09:03 PM
10/08/17 09:03 PM
Joined: Oct 2015
Posts: 440
MN
TmanP Offline
TmanP  Offline
Joined: Oct 2015
Posts: 440
MN
As I understand it, the SAE 30 is more resistant to breaking down in heat (due to the lack of viscosity improvers, which are only good for so long). So, while 5w30 is fine in summer, the ranking is probably
SAE 30>10w30>5w30 (for hot weather). This is why you will see SAE 30 used in lawn mowers. But, practically, there isn't too much difference and 0w30/5w30 can be used year-round.


2012 Toyota Camry 2.5 30,000 mi
2015 Chevy Silverado LT Z71 5.3 V8 30,000 mi
2010 Toyota Sienna 3.5 V6 150,000 mi
Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537523
10/08/17 09:04 PM
10/08/17 09:04 PM
Joined: Apr 2008
Posts: 37,188
Ontario, Canada
OVERKILL Online content
OVERKILL  Online Content
Joined: Apr 2008
Posts: 37,188
Ontario, Canada
An SAE 30 will have no VII (Viscosity Index Improvers) in it, which would make it immune to mechanical shear. However, generally your premise is correct in that there would be little advantage to using an SAE 30 over any of the grades you've mentioned.

Also, there are oils like Amsoil's 10w-30 that have no VII's in them and can also be labelled an SAE 30, muddying things further.


2018 RAM 1500 Big Horn EcoDiesel
2016 Grand Cherokee SRT
Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537540
10/08/17 09:29 PM
10/08/17 09:29 PM
Joined: Dec 2016
Posts: 453
Indiana
5AcresAndAFool Offline
5AcresAndAFool  Offline
Joined: Dec 2016
Posts: 453
Indiana
Ive always wondered if you had a situation where a vehicle was run around the clock most of the time, such as vehicles serving police, taxi, or ambulance duty, if you would be better off using a straight 30 weight oil.

How many miles on average before you see viscosity breaking down?

Re: I'm confused about the "cold" oil viscosity rating [Re: 5AcresAndAFool] #4537543
10/08/17 09:33 PM
10/08/17 09:33 PM
Joined: Apr 2008
Posts: 37,188
Ontario, Canada
OVERKILL Online content
OVERKILL  Online Content
Joined: Apr 2008
Posts: 37,188
Ontario, Canada
Originally Posted By: 5AcresAndAFool
Ive always wondered if you had a situation where a vehicle was run around the clock most of the time, such as vehicles serving police, taxi, or ambulance duty, if you would be better off using a straight 30 weight oil.

How many miles on average before you see viscosity breaking down?


If you look at oils designed for extended drain intervals like M1 0w-40, GC 0w-40...etc which are also a broad split on the visc side, it's easy to conclude that the straight weight may not offer any inherent advantage in that department. Where they do shine are in applications of high shear or where low cost is required, as they are cheap to blend, unlike a synthetic extended drain Euro oil.


2018 RAM 1500 Big Horn EcoDiesel
2016 Grand Cherokee SRT
Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537570
10/08/17 10:19 PM
10/08/17 10:19 PM
Joined: Oct 2016
Posts: 232
California
jj51702 Offline
jj51702  Offline
Joined: Oct 2016
Posts: 232
California
Probably cause there is a market for it

Re: I'm confused about the "cold" oil viscosity rating [Re: 5AcresAndAFool] #4537598
10/08/17 11:14 PM
10/08/17 11:14 PM
Joined: Sep 2015
Posts: 2,261
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,261
Malaysia
Originally Posted By: 5AcresAndAFool
How many miles on average before you see viscosity breaking down?

As low as several hundreds of miles of a multigrade in use.
Often times, it stays sheared-thin at the end of OCI of 5-10k.

Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537600
10/08/17 11:18 PM
10/08/17 11:18 PM
Joined: Jan 2007
Posts: 17,501
Clovis, CA
Merkava_4 Offline
Merkava_4  Offline
Joined: Jan 2007
Posts: 17,501
Clovis, CA
People are afraid of SAE 30 although it's one tough Hombre.
It costs more too since it only comes in quart bottles.

Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537625
10/09/17 01:08 AM
10/09/17 01:08 AM
Joined: Jan 2015
Posts: 129
Around the corner
koffy Offline
koffy  Offline
Joined: Jan 2015
Posts: 129
Around the corner
SO, volatility does not mean anything?

Re: I'm confused about the "cold" oil viscosity rating [Re: Avery4] #4537647
10/09/17 04:06 AM
10/09/17 04:06 AM
Joined: Sep 2017
Posts: 74
On your screen
OhOMG Offline
OhOMG  Offline
Joined: Sep 2017
Posts: 74
On your screen
Originally Posted By: Avery4
I am confused about why, for example, a 30w oil is available when a 10w30 or 5w30 would apparently work just as well when hot and work much better while cold. Would there be a disadvantage to using 0w30 in hot weather instead of SAE 30?


Generally, the answer to this question is no, there is no disadvantage to using the 0w30 in hot weather versus a 30-grade and yes you could use the 0W-30 year round.

Re: I'm confused about the "cold" oil viscosity rating [Re: OhOMG] #4537648
10/09/17 04:29 AM
10/09/17 04:29 AM
Joined: Dec 2002
Posts: 40,929
'Stralia
Shannow Online content
Shannow  Online Content
Joined: Dec 2002
Posts: 40,929
'Stralia
Originally Posted By: OhOMG
Originally Posted By: Avery4
I am confused about why, for example, a 30w oil is available when a 10w30 or 5w30 would apparently work just as well when hot and work much better while cold. Would there be a disadvantage to using 0w30 in hot weather instead of SAE 30?


Generally, the answer to this question is no, there is no disadvantage to using the 0w30 in hot weather versus a 30-grade and yes you could use the 0W-30 year round.


No disadvanteages ?
* Higher NOACK
* More VII to shear down in service
* Lower HTHS

a 20W20 would do...

Re: I'm confused about the "cold" oil viscosity rating [Re: OhOMG] #4537662
10/09/17 06:07 AM
10/09/17 06:07 AM
Joined: Oct 2012
Posts: 4,631
Taiwan
Ducked Online content
Ducked  Online Content
Joined: Oct 2012
Posts: 4,631
Taiwan
Originally Posted By: OhOMG
Originally Posted By: Avery4
I am confused about why, for example, a 30w oil is available when a 10w30 or 5w30 would apparently work just as well when hot and work much better while cold. Would there be a disadvantage to using 0w30 in hot weather instead of SAE 30?


Generally, the answer to this question is no, there is no disadvantage to using the 0w30 in hot weather versus a 30-grade and yes you could use the 0W-30 year round.


According to my handbook, I could use an SAE30 year-round, but I can't get it.

So I use an SAE40 year-round

Re: I'm confused about the "cold" oil viscosity rating [Re: Merkava_4] #4537709
10/09/17 07:13 AM
10/09/17 07:13 AM
Joined: Dec 2016
Posts: 6,262
Waco, TX
Linctex Offline
Linctex  Offline
Joined: Dec 2016
Posts: 6,262
Waco, TX
Originally Posted By: Merkava_4

It costs more too since it only comes in quart bottles.


What?!?!?!

Go to a farm or truck supply store....
1 gallon, 5 gallon, 30 gallon, 55 gallon are all READILY available.


"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: I'm confused about the "cold" oil viscosity rating [Re: Linctex] #4537718
10/09/17 07:24 AM
10/09/17 07:24 AM
Joined: Sep 2010
Posts: 7,009
Texas
4WD Offline
4WD  Offline
Joined: Sep 2010
Posts: 7,009
Texas
Yep = One of the common “tax free” lubes around here ...

Re: I'm confused about the "cold" oil viscosity rating [Re: Ducked] #4537740
10/09/17 08:04 AM
10/09/17 08:04 AM
Joined: Jun 2003
Posts: 17,371
Deplorable in apple valley, ca
Chris142 Online content
Chris142  Online Content
Joined: Jun 2003
Posts: 17,371
Deplorable in apple valley, ca
Originally Posted By: Ducked
Originally Posted By: OhOMG
Originally Posted By: Avery4
I am confused about why, for example, a 30w oil is available when a 10w30 or 5w30 would apparently work just as well when hot and work much better while cold. Would there be a disadvantage to using 0w30 in hot weather instead of SAE 30?


Generally, the answer to this question is no, there is no disadvantage to using the 0w30 in hot weather versus a 30-grade and yes you could use the 0W-30 year round.


According to my handbook, I could use an SAE30 year-round, but I can't get it.

So I use an SAE40 year-round
no 30wt?


02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
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