Oil Oxidizes Only During Use?
- Thread starter viscous
- Start date
Which are you asking? Your title says during use, but your question says sitting unused.
The rate of reaction is always doubled for every 10 degrees C. So at 210 degrees for hot oil and 30 gegrees for room temperature oil, the difference in rate would be 2E18!
BTW, that would be 262,144 times faster oxidation at 210 degrees than 30 degrees! So, happens at RT but almost at an imperceptible rate compared to 210 degrees.
Imperceptible as in it would last longer than you're going to live?
PimTac, you sure expect a quick response. I started this thread only a few hours ago! As my original question stated, I am asking about whether oil deteriorates, specifically oxidizes, while it's sitting unused in the vehicle. The thread title is appropriate, because if oxidation happens only during use, then it does NOT happen while the vehicle is sitting.
Five seconds on DDG.
www.machinerylubrication.com
Oxidation - The Lubricant's Nemesis
Oxidation is the most predominant reaction of a lubricant in service. It is responsible for numerous lubricant problems - including viscosity increase, varnish, sludge and sediment formation,...
www.machinerylubrication.com
As they say, oxidants happen 
As long as there is oxygen, oxidation will occur. Like @Boomer said, the rate varies tremendously depending on conditions with temperature being a huge factor. In general synthetics will resist stagnant oxidation better since they have more saturated bonds leaving less oxygen exchange sites.
As long as there is oxygen, oxidation will occur. Like @Boomer said, the rate varies tremendously depending on conditions with temperature being a huge factor. In general synthetics will resist stagnant oxidation better since they have more saturated bonds leaving less oxygen exchange sites.
It certainly does. For the purpose of defining a point, oil is "in service" once the seal is broken and its exposed to atmosphere. ( and its losing effect even before then albite slowly)
Now that brings a different set of questions that are not so simple. What specifically is oxidizing? What is the rate of oxidation? ( since we are now talking an "in service" oil we should switch to something like run hours over off hours against a linear timeline to trend the effect)
Then another variable is: Depending on what the oil is exposed to in operation ( everything from mechanical shear, temp, process chemicals, moisture, pollen, a stinky poot or whatever)- there can and usually will be varying rates of oxidation of various parts of the blend.
What its exposed to when working will have a definite effect and influence of rate of oxidation while sitting.
I see this a lot on base stock sampling of both "new" oils and oils in the drums ready for use.
Don't ever believe the oil you get out of the bottle is either clean or not in a state of degrading to some degree.
Thanks for the link, but can't we discuss this issue here as well? Is this thread offensive in some way?
Thanks, that was really my question. Would you say there is a meaningful difference between synthetic and conventional in this regard for a vehicle that will mainly be sitting unused?
Makes sense. I believe you've stated previously that there are other, more important, factors than dino/synth with regard to vehicles sitting unused. However, any reason to choose synthetic over conventional (or vice versa) for this application?
I believe it is every 10 degrees Celcius, not 10 degrees Fahrenheit.
Not sure what application you specifically are referring to but referring to dino v. S in terms of sump oxidation in general
I know of no reason either has a superiority in this category that I could promote with legitimate data.
We do tons of base stock samples ( almost all ISO but do have some motor oils) and I don't see any distinct difference or pattern regarding oxidation in a container. ( and this is with them in the same lube room)
The one exception in my experience would be lube rooms without climate control and more exposure to process chemicals and steam- they do tend to overcome desiccant breathers and have more issues in storage.
Thanks. Referring to a vehicle with minimal use, stored inside without climate control.
Yeah, I would say the difference between mineral and synthetic would be pretty imperceptible if it is just sitting unused. Without climate control, if you're in a humid environment, the moisture intrusion from condensation over time would cause more problems than oxidation.
and how does moisture get inside an engine if it's not running?
Humidity/moisture in the ambient air condensing during transitions from hot days to cool nights, etc.
Unless, of course, if it is sealed up and airtight.
Unless, of course, if it is sealed up and airtight.
10 degrees C = 18 degrees F. If your oil is at 210 degrees C you have bigger issues
According to Mobil temps of over 113F start effecting lubricant life.
I think you mean 113 C. My cars normal oil temp is 120 C.
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