What is a 5 weight oil?

[Blue99]

So, what is a 5 weight oil?

I get that “deer in the headlights” look when I see or hear this terminology.

I always assume that the phrase “10 weight oil” is a reference to SAE 10W. This is a viscosity I am familiar with as it is used at my workplace for air line oil in pneumatic systems. Also, I buy SAE 10W Non-Detergent to cut my chainsaw bar oil for winter time use.

But I’ve never run across an SAE 5 grade oil, or to use the proper current J300 designation, SAE 5W.

Going on the assumption that this is a reference to an older viscosity that is no longer included in the J300 chart, I searched on-line and found some background info on SAE J300.

Some J300 History by SAE
More Background

It reports that the original SAE J300 viscosity table was established in 1911 and was based on flow, in seconds, thru an orifice. After some time, the flow rates were converted to Poise or cSt. The SAE “W” ratings were added in 1952.

Here is an older version of J300, before W ratings:

code:

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SAE Flow Test Viscosity

Grade time in CentiStokes

(seconds) @ 100° C

10 under 14 4.00 ( 2 - 5)

20 15 to 24 7.45 ( 6 - 8)

30 25 to 34 10.90 ( 9 - 12)

40 35 to 44 14.40 (13 - 16)

50 over 45 19.10 (17 - 21)

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So, can anyone shed some light on the origin of this 5 weight terminology?

 

[1999nick]

A 5 weight oil is easy to understand. It would flow through the orifice of a given size in half the time of a 10 weight. What is hard to understand is all of these new 0 weights. How can anything but water, or maybe kerosene be 0 weight?

 

[Reg# 43897]

Well... wouldn't a '0w' oil flow through the same home at twice the rate of a '5w' oil? It's just a relative ranking of oils' viscosity after all, not an absolute number.

I could be very wrong here!

John.

 

[AEHaas]

They keep updating J300 to be current with technology. Here is more:

The Fuels and Lubricants Activity of SAE approved changes to the Cold Cranking Simulator (CCS) limits for multigrade engine oils as defined in SAE J300. The changes entail measuring viscosity at 5°C lower temperature and imposing higher maximum viscosity limits for all W-grades. The standard was modified based upon data demonstrating that modern passenger car engines start at lower temperatures and with higher viscosity oils than engines that were used to establish the previous CCS limits. The standard carries a revision date of December 1999. Mandatory compliance with these CCS limits begins June 2001. Until then, either the April 1997 or December 1999 CCS limits may be used to demonstrate compliance.

What this means is that a can of oil before and after that date and labeled exactly the same are different. The newer jar must be less thick at start-up than before in order to be in the same grade.

aehaas

 

[Blue99]

Keep in mind that water is the standard at 1.0 cSt.

Reference the older J300 chart. If SAE 10 (when it was a full viscosity grade) occupied the 2-5 cSt range, where does that leave room for a 5 weight oil?

And, yes, it would have to have a viscosity similar to kerosene.

 

[AEHaas]

Red Line has 2 and 5 wt. Racing oils. These have seen action in Formula 1 cars:

2 wt: 11 cS at 40 and 3 at 100 C
5 wt: 21.8 cS at 40 and 4.6 at 100 C

aehaas

 

[Blue99]

The Redline 2WT & 5WT are marketing labels for racing oils and do not indicate SAE viscosity grade.

Redline 5WT meets the viscosity requirement of a min 4.1 cSt @100c for an SAE 10W oil.

 

[AEHaas]

Red Line does label their 5 WT Racing oil as an SAE 0W equivalent. They have no SAE equivalent listed for their 0 WT oil.

One thing I have been trying to teach people is to look at the data sheets and not just the label. Look for the oil that gives you the viscosities and additive packages you desire.

aehaas

[ January 25, 2005, 03:10 PM: Message edited by: AEHaas ]

 

[Pablo]

I've been loitering in and reading all these threads....and to be honest....I wish we could do away with the whole XW terminology. Impossible, I know, but it sure would be nice to say my car needs a 12 cSt oil at 100°C, an oil that pumps at -X°C, with a HTHS of .....blah, blah... and selecting the closest oil....I can wake up now!

 

[XS650]

quote:

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Originally posted by Blue99:
Keep in mind that water is the standard at 1.0 cSt.

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At 20C. At 100C it's about 0.25.

 

[XS650]

quote:

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Originally posted by Pablo:
I've been loitering in and reading all these threads....and to be honest....I wish we could do away with the whole XW terminology. Impossible, I know, but it sure would be nice to say my car needs a 12 cSt oil at 100°C, an oil that pumps at -X°C, with a HTHS of .....blah, blah... and selecting the closest oil....I can wake up now!

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I would like to see them do it the ISO way where the viscosity rating is the actual viscosity in cSt +/- about 10%, except do it at 100C instead of 40C like they do now. Then add a temperature number in actual degrees that reflects the low temp capability of the oil.

For instance a 0w30 would be something like

"ISO 10-40C" Where the 10 means it's 10cSt +/- 10% tolerance at 100C and good for -40C use. I just made those number up, so they probabluy aren't right.

The present ISO system is part way there, except at 40C.
ISO Viscosity Chart

 

[AEHaas]

I like this idea.

aehaas

 

[ekpolk]

quote:

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Originally posted by Blue99:
{snip}
And, yes, it would have to have a viscosity similar to kerosene.

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No, not like kerosene. As I related in that "cold oil" thread in the main forum, a couple days ago, I pulled a 5k mile sample out of my G35. The oil is German Castrol, which is, of course, a 0w30 grade. Just for the fun of it, I pulled a second sample bottle full, and tossed it in the freezer to see what it would do. At room temp, this oil is almost indistinguishable from any 5w30 that you might choose to examine, as far as apparent thickness. I was absolutely shocked by what I found looking at the sample after it had been in my freezer for 24 hours. It was as thick and slow moving as a good quality, heavy maple syrup. It would still pour and spill quickly if the bottle were overturned, but I was still amazed at how thick it had become. I guess in my mind, I had formed a subjective expectation of how a "free flowing" 0w-x oil would behave when very cold. I was very wrong. And it's very much NOT like kerosene, room temp or freezing cold.

EDIT: Oh yeah, this got me so curious that as I type this, there's a new bottle of GC in my freezer taking the temp plunge. I want to ensure that the behavior of fresh GC is the same, for obvious reasons.

 

[AEHaas]

Ekpolk,
ASTM testing uses several methods to test lubricants in cooler conditions. Many tests involve several days of cooling, warming to room temp. then cooling again. They do this over a week in some of their tests. Then do the pour test but get a few different oils. I know it is hard to wait so long but I think it is worth it.

aehaas