Agree. That is why I use a LOT of 10w30 syn in various applications. Most of the 10w30 I use is essentially a straight 30w (or pretty close) that qualifies as 10w30. No evidence that it has been an issue in several years of year round use from 105F+ down to -25F, with most times the ambient temps well inside those spreads.
5W vs. 10W Synthetic Oil : Start Up Wear ?
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Doesn't matter. Use either one.
Originally Posted By: BrocLuno
Originally Posted By: CT8
Why would you think at the temps you mentioned would there be a difference in start up wear.
Start-up wear is not related to pumped oil. It is related to the residual oil film left when the engine is shut off. Pumped oil is a replenishment strategy, not a primary strategy.
Residual oil film is the key to longevity. You want the most robust oil film possible.
...
The same myths get repeated here over and over. In fact what causes startup wear has little to do with "oil film", it has to do with the caustic by-products of combustion that are not burned off at low temps during warm up.
And what evidence do you have that there is any better of a "film" of 10W-30 than 5W-30?
While not much of a difference, you're better off with a lower viscosity oil in colder temps...
Originally Posted By: CT8
Why would you think at the temps you mentioned would there be a difference in start up wear.
Start-up wear is not related to pumped oil. It is related to the residual oil film left when the engine is shut off. Pumped oil is a replenishment strategy, not a primary strategy.
Residual oil film is the key to longevity. You want the most robust oil film possible.
...
The same myths get repeated here over and over. In fact what causes startup wear has little to do with "oil film", it has to do with the caustic by-products of combustion that are not burned off at low temps during warm up.
And what evidence do you have that there is any better of a "film" of 10W-30 than 5W-30?
While not much of a difference, you're better off with a lower viscosity oil in colder temps...
I never said there was a difference. What I said was that the closer you get to 100% oil, the better off you are.
Some "syn" xW-30's may be only 40% Grp III and a bunch of dino oil with VII's, and that is not conducive to minimizing wear. Which is why I said pay attention to viscosity figures and HTHS as that will tell you about what's in the jug and the film strength.
And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
Some "syn" xW-30's may be only 40% Grp III and a bunch of dino oil with VII's, and that is not conducive to minimizing wear. Which is why I said pay attention to viscosity figures and HTHS as that will tell you about what's in the jug and the film strength.
And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
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Originally Posted By: BrocLuno
I never said there was a difference. What I said was that they closer you get to 100% oil, the better off you are.
Some 5W-30's may be only 50% Grp III and a bunch of dino oil with VII's and that is not conducive to minimizing wear. Which is why I said pay attention to viscosity figures and HTHS as that will tell you about what's in the jug and the film strength.
And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation. The parts I described never see "pumped oil" and they are the ones taking the beating ...
I got news for ya. Since the 1990's most R&D has gone into thinner oils like 5W-30 and the thicker old school oils never spec'd anymore don't get the love...
I never said there was a difference. What I said was that they closer you get to 100% oil, the better off you are.
Some 5W-30's may be only 50% Grp III and a bunch of dino oil with VII's and that is not conducive to minimizing wear. Which is why I said pay attention to viscosity figures and HTHS as that will tell you about what's in the jug and the film strength.
And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation. The parts I described never see "pumped oil" and they are the ones taking the beating ...
I got news for ya. Since the 1990's most R&D has gone into thinner oils like 5W-30 and the thicker old school oils never spec'd anymore don't get the love...
I never said anything about thicker oils. I said look at what's in the jug in terms of metrics. Even in 5W and 10W oils, there are vast differences between oils ...
Originally Posted By: BrocLuno
...And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
...And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
Originally Posted By: turnbowm
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
Not really. 540RAT starts out talking about wear and the importance of the anti-wear package. He then proceeds to test the oils at operating temps (100 deg C) as well as some at extreme temps of 275 deg F. So none of RAT's testing has anything to do with preventing 90% of the startup wear seen in a motor vehicle engine. It only proposes to test high loading at operating temp (ie causing wear scars). So it's ironic with 90% of engine wear occurring from cold start up to approx 175 deg F, that RAT's testing covers a temperature range much higher than that...and essentially a shock load such as might occur on loss of oil pressure/flow or even WOT/max rpm...or the other 10% of engine wear/failure modes.
Several things are going on during startup/warmup phase of a motor vehicle engine. And this is from what others have already posted before.
-Initial engine turnover and start where the cold pumped oil has not yet reached all intended locations
-Early startup where only the oil film (and chemical anti-wear deposits) and not oil flow are fully protecting bearings and metal to metal friction
-Engine slow warming where oil is not slung or gravity drained to remote locations not serviced by pressurized oil flow
-Final warmup in the 120-170 deg F range where the anti-wear/anti-corrosion add package is not hot enough to be optimized. Flow is established but not operating oil temperature. Corrosion and wear occurs until operating temp.
And there may be other inputs I've left out. The oil has to combat these combined effects.
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
Not really. 540RAT starts out talking about wear and the importance of the anti-wear package. He then proceeds to test the oils at operating temps (100 deg C) as well as some at extreme temps of 275 deg F. So none of RAT's testing has anything to do with preventing 90% of the startup wear seen in a motor vehicle engine. It only proposes to test high loading at operating temp (ie causing wear scars). So it's ironic with 90% of engine wear occurring from cold start up to approx 175 deg F, that RAT's testing covers a temperature range much higher than that...and essentially a shock load such as might occur on loss of oil pressure/flow or even WOT/max rpm...or the other 10% of engine wear/failure modes.
Several things are going on during startup/warmup phase of a motor vehicle engine. And this is from what others have already posted before.
-Initial engine turnover and start where the cold pumped oil has not yet reached all intended locations
-Early startup where only the oil film (and chemical anti-wear deposits) and not oil flow are fully protecting bearings and metal to metal friction
-Engine slow warming where oil is not slung or gravity drained to remote locations not serviced by pressurized oil flow
-Final warmup in the 120-170 deg F range where the anti-wear/anti-corrosion add package is not hot enough to be optimized. Flow is established but not operating oil temperature. Corrosion and wear occurs until operating temp.
And there may be other inputs I've left out. The oil has to combat these combined effects.
Originally Posted By: turnbowm
Originally Posted By: BrocLuno
...And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
I don't see it that way.
If you pull an engine down, even if it's been sitting for many months, you will get covered in oil, it's held there via capillary action and doesn't drain down like some proponents would have you believe...so for that first crank and initial operation, there's a reasonable amount of VERY thick oil proviiding hydrodynamic lubrication for bearings and skirts...Plus the tribofilm from last time it was operated is still there.
RAT's only testing something that is a bit like a solid lifter/cam interface...doesn't apply to bearings and pistons skirts (and probably not much to do with rings either).
Originally Posted By: BrocLuno
...And if you don't believe in residual film, what do you actually think keeps the metal parts apart for the first minute or two of operation? The parts I described never see "pumped oil" and they are the ones taking the beating ... They need something like 2,300 RPM to get enough sling oil. So the cold start idle time and easy drive off is all about residual oil film!
You and 540Rat seem to be on the same page regarding the importance of oil film strength in startup wear. I totally agree.
I don't see it that way.
If you pull an engine down, even if it's been sitting for many months, you will get covered in oil, it's held there via capillary action and doesn't drain down like some proponents would have you believe...so for that first crank and initial operation, there's a reasonable amount of VERY thick oil proviiding hydrodynamic lubrication for bearings and skirts...Plus the tribofilm from last time it was operated is still there.
RAT's only testing something that is a bit like a solid lifter/cam interface...doesn't apply to bearings and pistons skirts (and probably not much to do with rings either).
Safer bet is to run something that you can run all year around.
life gets in the way of all best intentions, so a two grade strategy will undoubtedly leave you somewhere you should have 5W in with a sump full of 10W...unless you are here in Australia, and 20W anything is pretty well fine.
life gets in the way of all best intentions, so a two grade strategy will undoubtedly leave you somewhere you should have 5W in with a sump full of 10W...unless you are here in Australia, and 20W anything is pretty well fine.
10W-30 was the default all-climate grade in this country for decades prior to the widespread adoption of 5W-30.
Engines started and ran just fine in cold weather and nobody worried about a 10W qualified oil being too thick.
Fleet vehicles often rack up heroic mileages because they see a lot of use and because the fleet will have its own techs to maintain them.
Since once they're on the payroll the marginal cost of the wrenches labor is nil, fleet managers will often have repairs done that might cause an average owner to scrap his vehicle.
We've done this at work with a couple of our fleet vehicles. Parts cost alone is a much easier pill to swallow than parts+hundred buck an hour book time labor, especially since after a tech has done something a time or two he'll beat book time every time.
Engines started and ran just fine in cold weather and nobody worried about a 10W qualified oil being too thick.
Fleet vehicles often rack up heroic mileages because they see a lot of use and because the fleet will have its own techs to maintain them.
Since once they're on the payroll the marginal cost of the wrenches labor is nil, fleet managers will often have repairs done that might cause an average owner to scrap his vehicle.
We've done this at work with a couple of our fleet vehicles. Parts cost alone is a much easier pill to swallow than parts+hundred buck an hour book time labor, especially since after a tech has done something a time or two he'll beat book time every time.
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If Tired Trucker can run 10w30 up there - I sure can. Folks argue CAFE impacts often - but long before we had grades and even BRANDS on fill caps - we had a very logical chart in our owners manual with a huge overlapping of 5w & 10w as it related to temperature. Well, wrt protection - not going to micrometer that brick. When I can get QS UD for $2/quart - 10w is the most awesome that day ...
Originally Posted By: ChrisD46
It would seem a safe bet to run 5W30 in Winter and 10W30 in Summer?
That certainly could work, but Shannow's point is important. Besides, at operating temperatures, you're going to have much the same viscosity in the first place. Multigrade oils are supposed to minimize or eliminate seasonal OCIs, not encourage them.
A 10w-30 isn't totally incapable in the winter. One just has to know one's climate. On the other hand, a 5w-30 is perfectly capable in the summer.
It would seem a safe bet to run 5W30 in Winter and 10W30 in Summer?
That certainly could work, but Shannow's point is important. Besides, at operating temperatures, you're going to have much the same viscosity in the first place. Multigrade oils are supposed to minimize or eliminate seasonal OCIs, not encourage them.
A 10w-30 isn't totally incapable in the winter. One just has to know one's climate. On the other hand, a 5w-30 is perfectly capable in the summer.
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