In your opinion,based on the knowlege we have from UOAs and oil/additive chemistry, which is more destructive to a gasoline motor oil...time or mileage ?
Which is more destructive to motor oil....time or milage ?
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Are you asking if a three month old oil with one 5 mile trip is in "better shape" than a Three days since oil change in which you have traveled 3000 miles?
Or are you talking about on a smaller scale. As in one day vs. 30 miles? A full OCI(time) vs. a full OCI miles?
Or are you talking about on a smaller scale. As in one day vs. 30 miles? A full OCI(time) vs. a full OCI miles?
The old myth, 3 mo or 3000K triggered an oil change. Is this because additive depletion(due to oil age) at 3 mo was worse than 3 thousand miles of driving ? In other words...do oil additives have a defined "life" even if the vehicle is driven less than the prescribed mileage ? Thanks for the comments and sorry for being foggy !
I would think that there are enough people on this site who have done a VOA, UOA @1000 mi, and UOA at a full OCI to give you a starting point.
Dr. Haas has a number of vehicles that I get the impression do not see excessive milage and it is very possible he could provide the counterpoint.
I have no data to back this up but would assume that moving oil from a plastic jug to an all metal environment would effect its longevity, through oxidation and other chemical interaction, but think that todays additive packages are probably far more stable than those of the past. Given the nature of the environment in which Modern gas engine oil perform I think a lack of the need to perform would have little effect in the short term.
Environmental factors may also effect oils' longevity. Humidity and temperature variance, etc. As, however, modern engines are sealed much better than those of the past. I believe todays engines would provide enough of a buffer to make this effect negligable.
Dr. Haas has a number of vehicles that I get the impression do not see excessive milage and it is very possible he could provide the counterpoint.
I have no data to back this up but would assume that moving oil from a plastic jug to an all metal environment would effect its longevity, through oxidation and other chemical interaction, but think that todays additive packages are probably far more stable than those of the past. Given the nature of the environment in which Modern gas engine oil perform I think a lack of the need to perform would have little effect in the short term.
Environmental factors may also effect oils' longevity. Humidity and temperature variance, etc. As, however, modern engines are sealed much better than those of the past. I believe todays engines would provide enough of a buffer to make this effect negligable.
I think that in general, it is USE that depletes oil, not the passage of time. Time limits have traditionally been placed on OCIs IMO for two reasons:
1) As a safety factor. In other words, by setting X miles or Y months, you are guarding against the chronic short tripper who puts a lot of contaminants/fuel/H2O into the oil but doesn't cover a lot of miles. But keep in mind that it is still the USE pattern that is degrading the oil...a time limit is used because miles aren't a good way to quantify this type of short trip use.
2) To sell motor oil. Pushing the "3 month" limit IMO is done simply to get you into the jiffylube 4x a year.
Note that in contrast to the '3 month' rule, vehicles equipped with Oil Life Monitors have a 1 year safety limit - precisely because the type of 'short trip' use that is damaging to oil can be more accurately measured by the OLM.
1) As a safety factor. In other words, by setting X miles or Y months, you are guarding against the chronic short tripper who puts a lot of contaminants/fuel/H2O into the oil but doesn't cover a lot of miles. But keep in mind that it is still the USE pattern that is degrading the oil...a time limit is used because miles aren't a good way to quantify this type of short trip use.
2) To sell motor oil. Pushing the "3 month" limit IMO is done simply to get you into the jiffylube 4x a year.
Note that in contrast to the '3 month' rule, vehicles equipped with Oil Life Monitors have a 1 year safety limit - precisely because the type of 'short trip' use that is damaging to oil can be more accurately measured by the OLM.
I ran a fresh load of Maxlife 4400 miles in two weeks and the UOA came out very nice. Now I have a load of Maxlife that has been in for over a year and also has 4400 miles. On the blotter it looks pretty good. No UOA data though. Of course there were little if any short trips, mostly very long trips and a few 10 to 20 milers.
Which confirms the knowledge that short trips suck, long road trips rule...
Yep, Dad2leia, I think you hit the nail on the head. The difference in effect on oil between long trip driving and short trip driving is far more significant than the difference between time and mileage.
But as mileage increases, combustion loading into the oil increases, and so time becomes more significant.
Time, yes, not as calender months, but engine operating hours. GM trucks now have engine hour meters, just like airplanes and industrial engines. Hours take into account idling and stop and go traffic vs highway use.
Well, it certainly took them long enough to add that nice little guage to the vehicles, didn't it?!? I can remember trying to figure out just how many idling hours were on my folks old '88 Voyager, because the thing had over 400K miles on it before they got rid of it. I lost track of how many drums of oil I changed on it.
To add to my last post, though, just go for a drive when you fire up the vehicle that you let sit for a week or two, and it'll be a lot less stressful on the oil in the crankcase.
To add to my last post, though, just go for a drive when you fire up the vehicle that you let sit for a week or two, and it'll be a lot less stressful on the oil in the crankcase.
The general idea is right.... The 3000/3mo rule is a failsafe and lube seller. For the simple minded, It should keep the engine running and the jiffy lubes in business.
Reality says that I can take an oil and run it at 60 miles per hour a couple of hours a day and both it and the engine will be in good shape in 10,000 to 15,000 miles (a good group II).
I can put it in an engine, run short trips, accumulating maybe 2000 miles in 6 months, and I will have an oil with high amounts of corrosion.
If I put it in an engine, circulate it, let it stand for 4 months, operate it for 500 hours off in the next 2 or 3 months, and it will be fine.
But if I run that oil for it's 500 hours and then let it sit for 4 months, I will have high corrosion.
I have a Toyota pickup I leave in another city for when I fly in. When I'm there, I drive a minimum of 100 km a day (home and back twice) plus client visits. But then it may sit for 6 to 8 weeks. I seriously reduced the corrosion by having it driven 50 km every sunday. (actually it was my 4Runner when I documented it all on UOA, but know I switched out the cities)
Reality says that I can take an oil and run it at 60 miles per hour a couple of hours a day and both it and the engine will be in good shape in 10,000 to 15,000 miles (a good group II).
I can put it in an engine, run short trips, accumulating maybe 2000 miles in 6 months, and I will have an oil with high amounts of corrosion.
If I put it in an engine, circulate it, let it stand for 4 months, operate it for 500 hours off in the next 2 or 3 months, and it will be fine.
But if I run that oil for it's 500 hours and then let it sit for 4 months, I will have high corrosion.
I have a Toyota pickup I leave in another city for when I fly in. When I'm there, I drive a minimum of 100 km a day (home and back twice) plus client visits. But then it may sit for 6 to 8 weeks. I seriously reduced the corrosion by having it driven 50 km every sunday. (actually it was my 4Runner when I documented it all on UOA, but know I switched out the cities)
Any one like to guess when the 3k/3-mo recommendation begain?...some time ago I gather. As changes are slow and for much in the way it has come to support businesses, the improvements that have come with lubricant and engine management systems, I suspect this 3k/3-mo recommendation nolonger as significant for the life of the engine as it once was. Manuals have been known to say 6 months to 1 year depending on the severity of service, while more recently I think I've heard of 18months to 2 years (Saab with M1).
It has been mentioned around here that frequent oil changing may lead to what the automotive industry is trying to minimize - catalytic converter poisoning. I think it has somthing to due with the lack of "aging" for the newly introduced ZDDP, but honestly I haven't the slightest.
I believe I have seen a few UOA's that with low miles, presumable from infrequent, distance use over a year to perhaps 4 years, and things still tested out well. Dino or synth. I can't recall, but I think the environment while in storage and the degree of engine operation between use (getting things fully warmed and evaporating any previous condensation out of the oil), have much to do with it...outside of the capability of the oil as has been previously mentioned by others.
It has been mentioned around here that frequent oil changing may lead to what the automotive industry is trying to minimize - catalytic converter poisoning. I think it has somthing to due with the lack of "aging" for the newly introduced ZDDP, but honestly I haven't the slightest.
I believe I have seen a few UOA's that with low miles, presumable from infrequent, distance use over a year to perhaps 4 years, and things still tested out well. Dino or synth. I can't recall, but I think the environment while in storage and the degree of engine operation between use (getting things fully warmed and evaporating any previous condensation out of the oil), have much to do with it...outside of the capability of the oil as has been previously mentioned by others.
Just to mix things up...
Storage in plastic versus metal container (crankcase) - well there are numerous material components that are coated and bathed in the oil where it lay within the engine's case, and for which additives such as metal deactivators will come into play to reduce oil degredation via electrolysis, yes? (There to is oxygen, sulfur, nitrogen, moisture,...to combate in the not-so-virgin mechine, but shall continue on the given path) Would it be safe to presume that temperature's a factor in this form of reaction, as it is the amount and types of material in suspension/creasting the surface interface? What are the effective durations of these additive types - sacrificial? TBN and/or TAN levels may be better predictors of the said additives abilities to stave off such "attacks" otherwise, yes?
With that said, I believe the greatest duration of oil's storability would be in a container whose construction is of one material, and a material that is not reactive, thus innert in relation to the base oil and all it's additives. Any use of this oil, for which would then have put matter of various elements and composition into suspension, would compromise it's continued effectiveness. Of course this compromise, as long as said contaminents are harmless to the oil and it's additives as well as the container's composition, could be filtered out. I wonder though as for any addivies if aiding to suspend these contaminent particles and of which remain bonded to the foreign matter and thus be captured by the filter, and being a sacrificial component that under careful and knowing attendence, could be replenished? I would think this replenishment likely, and for the argument against added additives, I see it against unknowing additions of that bring the mix beyond formulation values and intended compostion, yes?
A complex, interactive picture I suppose...but thought to be a moment in the life of a fluid lubricant.
Storage in plastic versus metal container (crankcase) - well there are numerous material components that are coated and bathed in the oil where it lay within the engine's case, and for which additives such as metal deactivators will come into play to reduce oil degredation via electrolysis, yes? (There to is oxygen, sulfur, nitrogen, moisture,...to combate in the not-so-virgin mechine, but shall continue on the given path) Would it be safe to presume that temperature's a factor in this form of reaction, as it is the amount and types of material in suspension/creasting the surface interface? What are the effective durations of these additive types - sacrificial? TBN and/or TAN levels may be better predictors of the said additives abilities to stave off such "attacks" otherwise, yes?
With that said, I believe the greatest duration of oil's storability would be in a container whose construction is of one material, and a material that is not reactive, thus innert in relation to the base oil and all it's additives. Any use of this oil, for which would then have put matter of various elements and composition into suspension, would compromise it's continued effectiveness. Of course this compromise, as long as said contaminents are harmless to the oil and it's additives as well as the container's composition, could be filtered out. I wonder though as for any addivies if aiding to suspend these contaminent particles and of which remain bonded to the foreign matter and thus be captured by the filter, and being a sacrificial component that under careful and knowing attendence, could be replenished? I would think this replenishment likely, and for the argument against added additives, I see it against unknowing additions of that bring the mix beyond formulation values and intended compostion, yes?
A complex, interactive picture I suppose...but thought to be a moment in the life of a fluid lubricant.
To consider ,Quality of oil to begin with,climate,distance,engine design,filter efficency,PCV valve,air filter,fuel octain ,proper oil level,driving habits,,play a part on how long a engine lube will be effective,,yes a very good oil can be degraded in say 7k if abused,,or a low end oil at 2k,though Im not a beliver on very extened intervals,20k plus,,most oils will work fine up to 5k or three changes per year,talking better end mineral and semi synt.,,,,,,,,BL
Quote, " Anyone care to guess when the 3mo/3K recommendation began ....some time ago I gather" Unquote.
My grandfather started a garage/gas station (Mobil-Flying Horse) sometime in the 1930's. He told me the standard OCI was 3 mo's but the milage was not an issue due to dusty unimproved roads(Texas). Straight 30 weight year round. It is my opinion the 3 mo has been around since the advent of combustion automobile engines.
My grandfather started a garage/gas station (Mobil-Flying Horse) sometime in the 1930's. He told me the standard OCI was 3 mo's but the milage was not an issue due to dusty unimproved roads(Texas). Straight 30 weight year round. It is my opinion the 3 mo has been around since the advent of combustion automobile engines.
Mileage because there is more time that it is exposed to the combustion process.
The oil is not being used when it's simply sitting. Whether in your engine or in a bottle, I can't see too much difference unless the car is in a hostile environment (eg. knee high water or open engine bay exposed to the elements or open intake stored outside, etc.).
The oil is not being used when it's simply sitting. Whether in your engine or in a bottle, I can't see too much difference unless the car is in a hostile environment (eg. knee high water or open engine bay exposed to the elements or open intake stored outside, etc.).
Heat speeds 99.9% of chemical reactions. Oil is inherently stable over a small temperature band an then becomes highly volatile. A good many of the additives in oil today are put there to widen this band and help the oil to maintain properties that would otherwise change as ambient and engine temperature vary.
This said, I think that these other factors (fuel,water, sulfur, etcetera) have more of an impact on the degradation of the additive package over drive time, thus bringing the oil closer to its original structure, and decreasing its effective lifespan.
It apears that the collective information from this thread would lead one to the conclusion that an engine hour meter may be more beneficial than time or milage. Similar to farm equipment.
The transition to computer-controlled, fuel injected vehicles has greatly limited the fuel load in the oil, especially from cold starting.
I believe that the 3,000 mile/3 month "rule" may still be applicable to carbureted vehicles, especially in colder weather, but it is obsolete on computer-controlled, fuel injected vehicles.
I believe that the 3,000 mile/3 month "rule" may still be applicable to carbureted vehicles, especially in colder weather, but it is obsolete on computer-controlled, fuel injected vehicles.
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