This is untrue, yes. Look at SAE J300, like I already mentioned. For example, a 20w-20 isn't exactly the same as an SAE 20.
Oil change question
- Thread starter daz
- Start date
- Status
OVERKILL
$100 Site Donor 2021
Originally Posted By: 4wheeldog
Originally Posted By: Quattro Pete
Originally Posted By: 4wheeldog
So, a 5w/30 acts like a 5 weight oil when cold,
No it doesn't. The first number is just a representation of how an oil will behave at a measured temperature which happens to be at -35C for a "5w". But it's a pumping viscosity, not to be confused with kinematic viscosity that is represented by the second number in the oil grade.
Saying that it acts like a 5 weight oil is inaccurate.
http://www.upmpg.com/tech_articles/motoroil_viscosity/
Read it again.......I don't think that article says what you think it does. It only acts like a 5 weight oil, when cold, as I stated. It may not be exactly like a 5 weight, but it is labeled 5Winter for a reason.
The number in front of the W is not a representation of an SAE 5 "when cold", which doesn't exist as a motor oil grade, neither does a 10 or a 15, all of which are a xW classifications. The same goes for a 0. Is there an SAE 0? No. The SAE grading system for oils under the non-W classification starts at SAE 20.
Just as an example here, Mobil 1 0w-40 and Mobil 1 0w-20 both carry the 0w designation. Which means they meet the cold temperature performance requirements for that classification. This classification is simply a set of limits for MAXIMUM viscosity at -40C and -35C respectively. That is the ONLY thing those two oils have in common:
M1 0w-20:
Visc@100C: 8.7cSt
Visc@ 40C: 44.8cSt
MRV@ -40C: 9,200cP
M1 0w-40:
Visc@100C: 13.5cSt
Visc@ 40C: 75.0cSt
MRV@ -40C: 31,000cP
Is 9,200cP close to 31,000cP? Nope. But they are both under 60,000cP at -40C (and under 6,200cP for CCS @ -35C), so they both get to carry the 0w designation. There is no temperature that M1 0w-40 is even CLOSE to the same viscosity as the 0w-20.
You'll notice the 0W and 5W designations have the exact same visc minimums @ 100C, with no maximums for 100C or HTHS. You'll also notice the distinct absence of an SAE 5, 10 and 15 grade on the chart
Those grades only exist as ISO hydraulic oil grades, not engine oils.
Originally Posted By: Quattro Pete
Originally Posted By: 4wheeldog
So, a 5w/30 acts like a 5 weight oil when cold,
No it doesn't. The first number is just a representation of how an oil will behave at a measured temperature which happens to be at -35C for a "5w". But it's a pumping viscosity, not to be confused with kinematic viscosity that is represented by the second number in the oil grade.
Saying that it acts like a 5 weight oil is inaccurate.
http://www.upmpg.com/tech_articles/motoroil_viscosity/
Read it again.......I don't think that article says what you think it does. It only acts like a 5 weight oil, when cold, as I stated. It may not be exactly like a 5 weight, but it is labeled 5Winter for a reason.
The number in front of the W is not a representation of an SAE 5 "when cold", which doesn't exist as a motor oil grade, neither does a 10 or a 15, all of which are a xW classifications. The same goes for a 0. Is there an SAE 0? No. The SAE grading system for oils under the non-W classification starts at SAE 20.
Just as an example here, Mobil 1 0w-40 and Mobil 1 0w-20 both carry the 0w designation. Which means they meet the cold temperature performance requirements for that classification. This classification is simply a set of limits for MAXIMUM viscosity at -40C and -35C respectively. That is the ONLY thing those two oils have in common:
M1 0w-20:
Visc@100C: 8.7cSt
Visc@ 40C: 44.8cSt
MRV@ -40C: 9,200cP
M1 0w-40:
Visc@100C: 13.5cSt
Visc@ 40C: 75.0cSt
MRV@ -40C: 31,000cP
Is 9,200cP close to 31,000cP? Nope. But they are both under 60,000cP at -40C (and under 6,200cP for CCS @ -35C), so they both get to carry the 0w designation. There is no temperature that M1 0w-40 is even CLOSE to the same viscosity as the 0w-20.
You'll notice the 0W and 5W designations have the exact same visc minimums @ 100C, with no maximums for 100C or HTHS. You'll also notice the distinct absence of an SAE 5, 10 and 15 grade on the chart
OVERKILL
$100 Site Donor 2021
Originally Posted By: Garak
This is untrue, yes. Look at SAE J300, like I already mentioned. For example, a 20w-20 isn't exactly the same as an SAE 20.
Exactly. An SAE 20 may not meet the cold temperature performance requirements to carry the 20W designation, and is of course then not a 20W-20, but just a straight SAE 20. Which throws that entire logical fallacy out the window.
This is untrue, yes. Look at SAE J300, like I already mentioned. For example, a 20w-20 isn't exactly the same as an SAE 20.
Exactly. An SAE 20 may not meet the cold temperature performance requirements to carry the 20W designation, and is of course then not a 20W-20, but just a straight SAE 20. Which throws that entire logical fallacy out the window.
Originally Posted By: daz
We know there are a lot of holdover ideas from days gone by that are no longer valid because certain things have changed. This seems like a stupid idea but it DOES seem to make sense. I like everyone have always changed my oil with a hot engine, waiting just long enough so that i don't burn myself. But back in the day when that idea was first born out of what seems obvious, oils were single grade. With today's multi grade it just hit me that draining oil cold with say 10w-40, the oil would be 4 times thinner ! Seems crazy to even consider a cold change, but why doesn't that make sense? What am i missing?
The whole hot vs. cold has been beat to death on here. I'm surprised that it's still a subject of debate.
Originally Posted By: BHopkins
Try changing the oil without warming the engine and see how it works for you. If you are OK with the extra time it takes to drain the oil, then go for it. If you are like me, and can't stand the extra time wasted while waiting for the oil to drain, then you will never do it again.
I can close the Fumoto valve and refill the oil.
Every oil change that I do is done on oil that is at room temperature or close to it. But then I've never been so lazy that I've had to install a little valve-I simple remove the drain plug, and in a minute or two all of the oil has drained. So quick that I normally don't get off the creeper-I simply wait a minute or two and it slows to a few drips, and then I replace the drain plug. So I guess I am OK with the very short time that it takes.
It works perfect for me every time.
We know there are a lot of holdover ideas from days gone by that are no longer valid because certain things have changed. This seems like a stupid idea but it DOES seem to make sense. I like everyone have always changed my oil with a hot engine, waiting just long enough so that i don't burn myself. But back in the day when that idea was first born out of what seems obvious, oils were single grade. With today's multi grade it just hit me that draining oil cold with say 10w-40, the oil would be 4 times thinner ! Seems crazy to even consider a cold change, but why doesn't that make sense? What am i missing?
The whole hot vs. cold has been beat to death on here. I'm surprised that it's still a subject of debate.
Originally Posted By: BHopkins
Try changing the oil without warming the engine and see how it works for you. If you are OK with the extra time it takes to drain the oil, then go for it. If you are like me, and can't stand the extra time wasted while waiting for the oil to drain, then you will never do it again.
I can close the Fumoto valve and refill the oil.
Every oil change that I do is done on oil that is at room temperature or close to it. But then I've never been so lazy that I've had to install a little valve-I simple remove the drain plug, and in a minute or two all of the oil has drained. So quick that I normally don't get off the creeper-I simply wait a minute or two and it slows to a few drips, and then I replace the drain plug. So I guess I am OK with the very short time that it takes.
It works perfect for me every time.
I was taught by my dad to loosen or remove the oil filler cap before removing the drain plug, so my experience is right in line with Pop_Rivet, except I've never had a creeper. I put the vehicle up on the ramps the night before I change the oil these days. When I was younger & skinnier I didn't need ramps for a truck, but I'd use a jack & jackstands for cars. Just change the next day after sitting overnight. Drains quick, plug back in, move to oil filter to remove.
This comment may or may not be relevant, but Blackstone prefers samples at operating temperature.
http://www.blackstone-labs.com/gas-sampling.php
Kevin
http://www.blackstone-labs.com/gas-sampling.php
Kevin
If you check out that link, that's in order to cook off any normal moisture or fuel buildup.
I have no problem draining oil with moisture and / or fuel in it and replacing that with fresh oil when I change my oil.
They also prefer samples taken at a specific point in the drain.
Is that because they think the earliest parts have the most contaminants and the last bits the least, or vice-versa?
Me, I've always been more on the side of best representative samples in my work life. If I was to submit a VOA, I'd pour my drain pan contents into a jug, then shake the jug up real well.
If this works for oceangoing tankers with capacities up to 126,000,000 gallons each, I reckon it'd be pretty representative of my drain contents.
I have no problem draining oil with moisture and / or fuel in it and replacing that with fresh oil when I change my oil.
They also prefer samples taken at a specific point in the drain.
Is that because they think the earliest parts have the most contaminants and the last bits the least, or vice-versa?
Me, I've always been more on the side of best representative samples in my work life. If I was to submit a VOA, I'd pour my drain pan contents into a jug, then shake the jug up real well.
If this works for oceangoing tankers with capacities up to 126,000,000 gallons each, I reckon it'd be pretty representative of my drain contents.
Last edited:
Meant UOA - still getting used to the acronyms here, I wasn't a lurker before joining.
- Status
Similar threads
