Shell put out this chart on the effect of oil temp on motor oil. It’s more of an advertisement than anything technical. There was no date on it. Enjoy.
Oil life vs temperature
- Thread starter Snagglefoot
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Pretty sure the laws of physics don't change very quickly, so it doesn't need to be dated.
It doesn't need a time dimension, it's relative. Whatever oil you run at 107°C can run twice as long at 97°C, or half as long at 117°C.
I don't understand why a chart would be needed for this though.
As it notes it is based on the generally true generalization that a chemical reaction rate is doubled for every 10°C increase in temperature.
I’m not sure what reactions they are referring to but I suppose Shell does.
I’m not sure what reactions they are referring to but I suppose Shell does.
Some vehicles have oil temp in their data. Not sure which are incorporating this into their OLM.
'Not that simple. It depends on the activation threshold or energy. A reaction may not even begin until a certain temperature is reached for a particular component. There are too may variables to make this global statement about the useful life of an oil based on the temperature.
ali
ali
Perhaps it's designed to scare people into more frequent oil changes? Kinda like LSJ shearing video.
The Arrhenius equation (not "Arrhenius rate law") doesn't state any such thing. Here's what it "states":
There's no mention of lubricants or oil life. Each chemical reaction taking place within a lubricant will be subject to this law (as well as others) and the overall effect may well be as stated, but then it's also difficult to track T for any given portion of oil as it transits the oil system and is exposed to various temperatures.
There's no mention of lubricants or oil life. Each chemical reaction taking place within a lubricant will be subject to this law (as well as others) and the overall effect may well be as stated, but then it's also difficult to track T for any given portion of oil as it transits the oil system and is exposed to various temperatures.
That’s not how it works.
I know! Was just converting 10F to C like one of our members used to do anytime someone said xF degrees!
That's why I said in "absolute" terms.
I've seen charts like this many times for ATF but never for engine oil till now!
Is it because engine oil has to deal with other factors like water/coolant, fuel, combustion byproducts, dirt, etc. In which these kind of charts can not be universally applied?
Is it because engine oil has to deal with other factors like water/coolant, fuel, combustion byproducts, dirt, etc. In which these kind of charts can not be universally applied?
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So what are we supposed to glean from this as far as optimal oil temp and optimal oil life go?
MolaKule
Staff member
Not much. Different Anti-oxidant types degrade at different rates. There too many variables to glean anything from this chart.
So keep the oil at 107F at all times. Got it, thanks.
My 6.0 Chevy gas engine with my 3/4 ton came with oil cooler lines to the rad. In spite of the engine having almost 400 lb ft of torque the transmission drops a couple of gears and the engine will rev at between 2500 and 3000 rpm when towing. The coolant temp stays at close to 210 F no matter what the rev’s are but the oil temp climbs above 210 F. The viscosity of the oil is lessened and if you believed the chart, oil life would be compromised.The oil cooler tries to bring the temp back down towards 210 F.
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Yes, haven't towing or track etc. always been considered "harsh conditions" ergo shorten OCI.
This chart is just generalizing, probably several high-end oils that fair better then standard group III oils.
The max oil life even IF you don't drive your car, is 1 year*!
Please Note:
This is based on a VERY complex equation the oil companies have came up with.
It's been a while and I just recall the first part of the equation:
$ = [# of suckers born / min + (Existing suckers) **n] x profit per quart ...
Back of my M1 EP 10W-30 jug:
"*Protects for 20,000 miles or one year, whichever comes first."
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