Shelf life of opened oil?

Patman

Staff member
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21,989
Location
Oakville, Ontario
I know we've discussed the fact that oil has about a 4-5 year lifespan in sealed containers, but what if it's open? What could go wrong with it if it's kept in a relatively stable environment (such as in your basement) I've got a bottle of Schaeffer Oil with about 3/4 of a quart in it, but I don't anticipate using it for about a year (when I switch my wife's car from Royal Purple over to Schaeffer oil in fall 2004 that is) I hate to waste 3/4 of a quart, but if the oil isn't going to be safe to use I need to know that too.
 

Al

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19,161
Location
Elizabethtown, Pa
The only thing that could occur would a bit of water absorbtion . I wouldn't think it would be significant since when it is bottled the relative humitity is probably not controlled and there already me be some moisture in it. Just a guess though [Smile]
 

Patman

Staff member
Thread starter
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21,989
Location
Oakville, Ontario
quote:
Originally posted by FowVay: I agree with Al, I don't see a bit of trouble keeping the oil as long as it's in a sealed container. Even if it does get a bit of moisture in it from the air it won't be any different than what occurs naturally when your engine vacillates with temperature changes. And besides,, it'd be a darned shame to waste nearly a full quart of Schaeffers. Maybe you could do a lawn mower/snow blower oil change just for the heck of it and put the oil to good use.
I live in a condo townhouse, so there is no snowblower or lawnmower here. [Smile] Plus I do want to use the oil in my wife's car, so I won't put it anywhere else. The bottle is closed up good, and inside the original 12qt case, plus it's also in a closed drawer in my oil shrine (which is an old entertainment unit) which is in my laundry room. The temperature and humidity in there is pretty consistent all year round. So by the sounds of things I should be pretty safe I guess? I guess I might've been worried that somehow the TBN of the oil might drop slowly once the seal has been broken. I guess this isn't the case?
 
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5,358
Location
Gone
Patman, I don't think exposure to air should introduce anything that would affect TBN. From an overall perspective, I don't see how anything but added moisture from very humid air could be introduced. There is nothing in fresh oil with which moisture should react, right...e.g. to create acids? As long as it is quickly and tightly recapped, I think it should be OK.
 
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243
Location
Reno Nevada
A high TBN oil could, in the presence of moisture, absorb CO2 from the atmosphere as carbonate (an acid). TBN is typically maintained by an over based calcium carbonate system in most oils. While the excess base could theoretically become neutralized by C02 from the air, I doubt this would occur at a significant rate.
 
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2,908
Location
Georgia/Retired
I agree with Al, I don't see a bit of trouble keeping the oil as long as it's in a sealed container. Even if it does get a bit of moisture in it from the air it won't be any different than what occurs naturally when your engine vacillates with temperature changes. And besides,, it'd be a darned shame to waste nearly a full quart of Schaeffers. Maybe you could do a lawn mower/snow blower oil change just for the heck of it and put the oil to good use.
 
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3,317
Location
Bolivia
No problem for that period of time in a well sealed bottle. It will be a little darker when you open it from contact with the air you added. I know some people who by drums of oil to same money, but then take 2 years to use it. By that time it is considerably darker.
 
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76
Location
Sydney Au
how about use that extra quart to "flush out the old engine oil"? this is what i do drop oil, and empty the oil filter. then put back the sump and old oil filter back in. then i put in the 'extra' oil... and let it fall all the way to the bottom.. wait around 30minutes... then release the sump plug and change the oil filer per normal this will dilute alot of the old oil in your engine. cheers [Coffee]
 
Messages
100
Location
Palatine, IL
A few weeks ago I posted a UOA on some Mobil V Twin that sat in the motorcycle's oil tank all winter and then was run over the summer. The UOA was OK. If an oil will do that it certainly should be all right sitting in a closed bottle. [Big Grin]
 
Messages
1,533
Location
Ephraim
quote:
Originally posted by Patman: I know we've discussed the fact that oil has about a 4-5 year lifespan in sealed containers, but what if it's open? -*-*
Sir, I have had many a gallons of oil go un opened and opened and mixed... for a long time. For years and years. The think is if it is in a plastic container (metal rusts) if you keep it filled the better but on the other hand I have gone with 1/2 full containers until I couldnt walk around the front door and the converted them into bottles... I wait til I have a lot of bottles to do and then do them all at once... Soon I need to pour the fuel treatment into my containers.... I have about 50 containers and I end up spilling some ans such but I get my Wife to help... anyway... I have not in my experience seen any problem at all unless you leave them outdoors or in metal.
 

Mic

Messages
34
Location
Minnesota
This is what I read once. Our oil is a combination of one or more base oils and a complicated additive package. The base oils will actually last, many hundreds of thousands of miles, several years. The reason we have to change our oil is the additive package wears out. I think that is why they can recycle oil. I do not think you have to worry about the time frame you let unused oil sit on the shelf.
 
It appears from my UOA thatoil lasts a long time just sitting in an engine. This oil was in for 6 years, the oil was likely in the jug at least a year before I used it. The TBN was still over 7. http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=26;t=000058 This engine will be likely stored for a few years and I added some more fresh 7-8 year old oil mixed with more recent oil. I have some 21 year old oil in an engine, I should get a test on just to see if it still has a TBN left, maybe it is just a myth oil dies with age?
 

TC

Messages
1,644
Location
California
This comment by Shell Oil is interesting in that it also addresses brake fluid, which is hydroscopic (attracts moisture from the air), answering a question I've always had about "stoppin' juice." "Q: Is it safe to use motor oil, brake fluid, transmission fluid and other lubricants that have been opened, re-sealed and stored for several months?" "A: Any partially-used bottles of motor oil, brake or transmission fluid may be used for as long as three years after purchase. However, the product should be capped tightly and stored in a dry place, away from moisture." http://www.shell.ca/code/motoring/tips/lubricants.html
 
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