Does oil degrade with time?

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This may be a dumb question, but one that I have never really thought about and I'm sure someone can explain to me. Why are OCIs based on time as well as miles. Does the oil degrade while sitting in the engine unused over time?
 
I don't think the oil itself necessarily degrades with time. Time, after all, is what you need to make it. But apparently acids build up over time inside an engine. This is what I've been told as the time factor... but it seems that some simple additives could take care of that.

I think the 3 month recommendation is dated.
 
I have always wondered if the 3 month recommendation was clever marketing years ago that has turned into "fact".
 
I don't worry, but then my stash is in the cellar where it neither gets extreme cold or extreme heat. Shake it good before pouring in engine just in case some additive settled out over the years. I have stash that is 4 years old and before I use it all, some will prob be pushing 10 years. I don't worry about it. I have had oil co reps, like Valvoine, tell me that the shelf life is indefinite.
 
Once ran in the engine the oil has to deal with contamination, combustion byproducts and moisture. All of these deplete the additives in the oil over timed.

In storage oil should be good for 5 or so years depending on storage temperatures and the types of additives used. The oil itself never goes bad and can be recycled and reused indefinitely following proper purification process such as hydroprocessing.


In the engine the oil doesn't "go bad" It becomes contaminated and the additives that fight contamination and acid build up and act as antiwear and friction modifiers wear out causing the oil to be less effective as a lubricant and corrosion inhibitor.
 
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Oh yeah, should have read the question. In the engine I have run oil for 1 year with no aparent problems. Only not if it's a short trip vehicle a mile here 3 miles there.
 
The hardware store across the street is selling Valvoline 10W-40 Conventional Turbo-Approved in a white bottle. The promo contest printed on the bottle is to win a racecar... All entries must be received by Dec. 31 1997.

I bought 2 bottles and ran them in the generator... they did well enough.
 
I have Motul motorcycle oils that I bought in 1993 that I am currently running in my 08' CBR1000RR. The bike is running fine and dandy and dangerously fast.
 
I have an opened bottle of RL that has been sitting for about a year. Today I noticed yellow streaks (like sweat off the cap) outside of the bottle (a very thin film). Could that be the residue from the time I poured the oil?
Is the oil still good?
 
Probably residue that was along the top of the threads where the cap screws on, that dripped down over time. I keep a lot of old oil bottles from my oil changes, and once in a while you get that happening. On older bottles of Valvoline, the cap & tamper-proof ring likes to become discolored once the bottle is opened and poured. I'd say it's still good.
 
Don't throw it out. I would just use it, but if you want to call Redline the chemist will assure you it is okay (assuming it is, which is a very good assumption).

I once called Redline because the ATF I bought had a horrible odor, they checked the production code off the bottle and said yes this one is stinky from the seal condition used and that it is fine.
 
I'm running Mobil 1 10W-30 in the Lawn Mower that is API SE rated I think, no problems, I have 2 qts left and will use them next year. They were laying in a box I found when cleaning up the garage.

Frank D
 
Originally Posted By: pioneer
I have always wondered if the 3 month recommendation was clever marketing years ago that has turned into "fact".


Some of it, yes. I believe it was Jiffy Lube who coined the 3 months or 3,000 miles mantra, back in the early 1960s (I did a report on this for work a while ago, and I don't recall the exact date). Anyway, sure, they were trying to get business.

But on the other side of that, yesterday's oils were very crude, so to speak, compared with today's oils. Sludge was not uncommon, even in "well-maintained" engines. Yesterday's engines, also, were much harder on oil than today's engines are, what with straight-cut gears in the oil pumps, solid lifter and flat tappet valvetrains, etc.

Today's oils are much better, and today's engines are much easier on oil.
 
Originally Posted By: pioneer
This may be a dumb question, but one that I have never really thought about and I'm sure someone can explain to me. Why are OCIs based on time as well as miles. Does the oil degrade while sitting in the engine unused over time?


in terms of "time" and disregarding "miles". you can safely keep oil in the engine for 6-12months. i wouldnt go longer then 12months with a synthetic oil and no longer then 6 months with a dino. this also depends on your driving style and conditions and climit. for me, i will be going every 6months(which will be probably less then 5,000 miles)

the whole "3 month" story is total [censored]. maybe oil back in the days like 15yrs ago needed to be changed every 3 months yes, but not now-a-days.
 
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