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Kirkland 5W-20 vs 0W-20
- Thread starter glenncarpenter
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Yes. I’m very sure. The majority of engine wear happens on start up. So going to a 0w for cold flow helps prevent wear.
Any talk of viscosity modifiers in a PCMO product with a 5000 mile oil change interval, is literally splitting a flees hair. It’s not going to matter at all. And bringing it up is way over thinking it.
If OP said he had a fleet of 500 cars. And wanted to extend his oil drain intervals to the max length, while not moving the B10 of his fleet. Then we could have a discussion about HTHS, additive life span, etc.
But, 5000 miles is around 100-120 engine hours. That is a very safe oil change interval.
Maybe at temps well below 0, sure. But for most climates, as long as the oil can pump, lubrication should not be an issue.
However, most 0W-xx oils will have a lower kinematic viscosity during the warm-up phase than their 5W-xx or 10W-xx, and that may pose an advantage for fuel economy.
This graph starts at 160f. And it will always be lower viscosity than a 5w. Which means it will flow faster and provide better lubrication.
I could special paper all of them. But it’s really pointless for pcmo with short oil change intervals. 0w20 will be fine and have better cold flow over a 5w20.
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The viscosity difference between 50f and 150f is fairly significant for any grade of oil, so the minute differences in viscosity between a 0W-xx and 5W-xx of the same grade (during warm up) doesn't support your theory of reduced wear.
It’s not a theory. There are tons of engine sequence tests done that prove lower viscosity oils on start up, reduces engine wear.
Either way, it’s still a much better argument than splitting hairs over viscosity improvers in an additive package.
Flow faster?
The majority of wear does not occur at startup. The wear rate may be high for a momentary few seconds, but it's a blip on the radar of total engine wear. The bulk of engine wear occurs during the warmup period when the oil temperature is too cold to facilitate good additive response and the oil is easily contaminated with fuel and water dilution. I agree with most everything else.
I consider anything from ambient outside temperature to regular operational temperatures - “cold flow.”
So I supposed we’re actually saying the same thing. As cold flow to me, that 80f / 100f / 140f range. Before your anti wear additives become active, before… “operational” temperatures. Thus, old. I assume a more binary look at it - it’s either cold flow, or operational temperatures. (Or over heating in… bad cases.)
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I suspect that's never really been true. Maybe sort of true back when it was first said, in the days of extremely dilutive carbureted start-ups and primitive oils, but not really true at all now with universal fuel injection and modern quality oils. Also I've noticed that good oiling systems really don't need time to pump-up, they pretty much flow immediately once the starter begins to crank.
It’s been covered… countless times, from different angles, in TLT.
With your credentials, I respect your expertise... but I'm really struggling to understand this.
For the purposes of conversation, let's use Mobil 1 0W20 and Mobil 1 5W30 for comparison
Mobil 1 0W20
Vis @100C= 8.1 cst
Vis @40C= 43cst
Mobil 1 5W30
Vis @100C= 10cst
Vis @40C= 56.9 cst
Are you suggesting that at 40C, M1 0W20 will deliver superior wear protection to M1 5W30?
Both engine oils are significantly thinner than 43 or 56.9 cst once warmed up, so I fail to see how this matters. Do you have technical papers that I can look into? Thanks.
wemay
Site Donor 2023
Absolutely no discernable difference between these two for the life of the vehicle unless we're talking extreme cold start-up temps.
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Well, yes I'm generally aware of what analysis can reveal, and I think you may be doing it a bit of a disservice. The quantities of zinc, molybdenum, calcium, sodium, and other elemental components can reveal quite a bit about additives the oil contains, and non-spectrographic results like viscosity at different temps, flash point, etc give a good idea of the characteristics of the base oil. A very useful tool, though I agree, not a list of additives.
Your question isn’t apples to apples.
OP was comparing a 0w20 to 5w20. Both are going to be in the 8Ish cst range at operating temperatures. And we’re assuming that OP’s engine, calls for, a Xw20 from the OEM. Which has done testing to certify that product for proper wear protection. In this case, it is perfectly acceptable, arguably, better, to go to a 0w20, instead of using a 5w20.
Now if you’re asking me if I would use a 0w20, in a vehicle that calls for a 5w30 - no. I would not drop viscosity grades unless there was an extreme reason to justify it - such as the oil never actually getting to operational temperatures.
Now, does a 0w30 provide better protection than a 5w30? Yes. In my opinion, a 0w30, again, due to loss of flow from friction, oil pressure vs volume. You might have proper oil pressure - perhaps even high pressure, but you may not be receiving proper oil volume of flow. Which can lead to hot spotting and such in areas.
This is why large industrial systems have pre heaters, or oil heaters throughout their system, especially if it’s a large system.
So, why am I even saying this? Well, let’s start from coldest to warmest.
Cold pour point vs cold flow point vs what is actually safe to run your engine at: https://www.stle.org/files/TLTArchi...bsiteKey=a70334df-8659-42fd-a3bd-be406b5b83e5
Shill alert: I know the author. (No it’s not me.)
Just because a fluid is rated down to a certain temperature, doesn’t mean it’s safe to run. As well, the viscosity starts increasing quickly, as we get lower than 40c. Which is why (most of us) we prefer synthetics. And also why certain cold tests are so important to OEMs like cold crank.
Why am I not worried about viscosity index improvers?
Tech Beat
www.stle.org
There’s a lot of topics covered in that article.
It’s a good read. I don’t have enough time to type out allll the key take away from it on my phone.
Finally: https://www.stle.org/files/TLTArchi...bsiteKey=a70334df-8659-42fd-a3bd-be406b5b83e5
Low viscosity engine oils in heavy duty applications. They reduce friction, which means you’re reducing wear.
There’s tons of other articles. I’m not sure if TLT is pay walled or not as I’m logged into stle. However, they have a good search engine. You can just type in “engine wear” or “cold flow” and it will pull up articles.
But, increasing the Flow of oil, at “cold start” - which is ambient temperature, can reduce wear significantly. I’ve seen numbers up to 800%. However, that was from a book I have. Which I would need to scan as “proof” - so, I’ll just leave it at can reduce wear significantly.
You are shopping store-branded oil and worried about base-oil quality?? You are worried about the wrong thing. If you worry about base-oil quality, use a proven brand such as Mobil 1 or Pennzoil Platinum or go boutique.
0W-20 is better than 5W-20 because the former is thinner during warm-up and/or short trips, which is especially important for HEVs and PHEVs, in which the engine hardly ever warms up. Use 5W-20 only if you are driving fast for long distances or towing.
Adnoc via Vertex III’s are perfectly fine. They’re right up there with SK/Motiva and Petrocanada III’s.
Spec sheet - warning, PDF:
Keep in mind that a 0W-20 will have a lower viscosity base oil and thus typically more volatile. At what point do you start trading warmup wear for ring coking and cylinder wear?
I don't think startup viscosity really matters if you don't live in a cold climate. Whether a 20 grade oil has a KV40 of 48 cSt or 52 cSt is likely insignificant to someone living in Florida or SoCal. In such a case, I'd rather have the less volatile 5W-20. (or 10W-20 where available)
I don't think startup viscosity really matters if you don't live in a cold climate. Whether a 20 grade oil has a KV40 of 48 cSt or 52 cSt is likely insignificant to someone living in Florida or SoCal. In such a case, I'd rather have the less volatile 5W-20. (or 10W-20 where available)
Coking and varnish has more to do with formulation of additives then oil weight. At least when you’re comparing full synthetics.
There is also several tests that an approved additive package would go through to verify they’re not coking up. Such as D7097.
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