Mobil & Amsoil recommend OCI at 1 year or xxk miles, whichever comes first for their extended drain synthetic oil. Why 1 year time limitation? What happens after a year? If you drained the oil at 6 months (due to vehicle warranty requirement) could you bottle it, save it for a year or two or indefinitely, then use it (provided it was in plenty good shape when drained) in another vehicle for another 6 months or xxk total miles, whichever came first?
Why 1 year time limitation on OCI ?
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I previously posted my brother-in-law's UOA of is 1999 Boxter Porsche's factory oil that went 5 years and 9,000 miles. Considering the mileage, time and it being the factory oil it did da*m well. Not sure of the oil but it seems to have been a European Mobil 1 5W-40. Not the current 5W-40 Truck & Suv formula. How the vehicle is driven most likely determines the longevity of the oil.
Whimsey
Whimsey
There is nothing magic about 365 days. It is indeed a precautionary time amount. Lots of thermal cycles in that amount of time.
I don't know about your re-use plan. I suppose it would work. Confirm with a used oil analysis. I just don't like the contamination potential.
I don't know about your re-use plan. I suppose it would work. Confirm with a used oil analysis. I just don't like the contamination potential.
The one year limit is to keep folks that do 5 thousand a year from leaving it in the oil pan for 5 years. Its a dual limit 25K or 1 year...not many folks do 25K a year, but the verbage sounds good. I personally think a 2 year limit is more in order for those that do the average of 12K a year.
I am sure also the concern is contamination of the oil if left in for many years. I drained Mobil 1 from a vechile and used it again in another. It had 5 thousand on it. But clean is the method you need to follow to keep the oil from being contaminated when removed.
I am sure also the concern is contamination of the oil if left in for many years. I drained Mobil 1 from a vechile and used it again in another. It had 5 thousand on it. But clean is the method you need to follow to keep the oil from being contaminated when removed.
Leaving the oil in for 5 years or for many years isn't the issue here. The issue is why is more than a year too much? Why can't you leave it in for 18 months to 2 years, for example. I don't buy the "lots of thermal cycles in a year" argument either. The number of times people start up an engine in a given period of time varies enormously. What about people who only start the engine 2-4 times a day on average, or less, as against, say, 10-12 times a day on average? I suspect that the the 1-year rule is similar to the "change your oil every 3,000 miles" rule. Its outdated given the fact that today's oils are much better than those of the past, and any set period of time rule is unnecessary. Why not have a bracket of time rule that takes the important factors into consideration, such as we have for the general rules for how long to run an oil filter or air filter?
its a safety net basically. what if you have a coolant leak. it would be better to change oil once a year with a coolant leak than once every 2 years or 5 years. what if you have fuel dillution, or a dirty air filter. frequent oil changes will reduce the impact of those unforseen items.
in reality you can run an oil for 2 years 5 years or 20 years as long as the oil analisis looks good and you dont have any unforseen problems.
the problem is, its AWALYS the unforseen problems which end up biting you in the rear end.
give you an example, my dads classic chevy has oil over a decade old in it. he starts it every year and drives it for a couple months and puts it away. why change it? oil sits in the ground for millions of years exposed to alot worse things than whats found in an engine and yet it does not go bad. he has no coolant leaks, or bad filters, no fuel dillution problems, etc. he figures theres no point in changing it sence he puts so few miles on it each year.
in reality you can run an oil for 2 years 5 years or 20 years as long as the oil analisis looks good and you dont have any unforseen problems.
the problem is, its AWALYS the unforseen problems which end up biting you in the rear end.
give you an example, my dads classic chevy has oil over a decade old in it. he starts it every year and drives it for a couple months and puts it away. why change it? oil sits in the ground for millions of years exposed to alot worse things than whats found in an engine and yet it does not go bad. he has no coolant leaks, or bad filters, no fuel dillution problems, etc. he figures theres no point in changing it sence he puts so few miles on it each year.
Saab says you can go 2 years on their GM Long Life oils or up to 18,000 miles. My OLM shows days left counting down from 720 days!
Thanks for the replies. I feel better about (cleanly) draining/bottling/reusing Mobil 1 Extended Performance or (especially)Amsoil HDD &/or ASL. This will be with Mobil 1 Extended Performance oil filter & Amsoil EA air filter if/when available. I'll plan UOA after 2nd 5k & go from there.
The one-year OCI (I personally subscribe to a 6-month limit) is mainly for city driving, short trips, etc.
I have a friend who bought a Dodge/Cummins then became disabled. He now only puts on about 5K a year. His ten year old truck now has 70K on it. I did an oil change at 18 months which was just over 6K miles and included two winters. Because of the time and way he drives it, I expected some issues, so I had a used oil analysis done. It came back fine and even though as old as it was and at the recommended mileage limit for Cummins, was "suitable for continued use"!
Of course if a used oil analysis says all is well, then the 12 months becomes moot, irrelevant.
Please allow me to clarify "Lots of thermal cycles".
I don't necessarily mean just engine on and off cycles. I mean weather and diurnal cycles. Depending on climate, water vapor can easily deposit liquid water on relatively cool metal surfaces overnight. This water in combination with combustion by-products forms acids and other compounds. This worries oil companies.
Please allow me to clarify "Lots of thermal cycles".
I don't necessarily mean just engine on and off cycles. I mean weather and diurnal cycles. Depending on climate, water vapor can easily deposit liquid water on relatively cool metal surfaces overnight. This water in combination with combustion by-products forms acids and other compounds. This worries oil companies.
Kestas
Staff member
Not always. Before using oil as a natural resource, it was sometimes pooled on top of the ground. All the easy stuff has been drawn out. What's left now is mostly stuff that's under pressure.
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