out of shelf life oils

[Shannow]

Once you have broken the foil seal, the length of sealing surface in the tight bottle cap, separating the oil and the ambient is reduced from mm of glued surface to a semi plastic cap/bottle edge.

Diffusion takes care of the rest...that's what happens with brake fluid, oil takes another couple of things rather than ust a reduction in boiling point.

Add it to oil, bugs like to grow too.

OEMs are giving their take (conservative, just like the shelf life on your milk) as to how long that their product can be predicted/suggested/expected to do the job that the were intended to do under a range of conditions that they have no control of.

"Shaking" before you use is a great idea...but people buy oil in 20L drums, 205L drums, bulkies, by the tanker load...

 

[HerrStig]

Originally Posted By: RiceCake
I'd just worry with it being open you run the chance of moisture building up in the container. Sitting in the garage, hot, cold, hot, cold, hot cold every spring fall and winter could theoretically cause you an issue. I just know with brake fluid this is usually standard operating procedure; once open use it because the metal foil is the real sealing point.

No moisture ever builds up in an engine crankcase though.

 

[Tempest]

Many new transmission fluids are supposed to be "lifetime". However many years that will be will vary, but years and years in an active transmission.

I would think that motor oil would be nearly indefinite on the shelf so long as it has been stored properly and not opened.

 

[benjy]

on the early 90's mobil 1 that was prolly a true synthetic which store longer especially when temp is pretty constant, after castrol won court battle in 1999 most "synthetics" reformulated to cheaper group III dino oils now LEGALLY called synthetic, prolly same reason "synthetic" factory fills on a new engine is OK since its dino oil and not the slipprier true Group IV-V synthetics

 

[Tempest]

Originally Posted By: benjy
on the early 90's mobil 1 that was prolly a true synthetic which store longer especially when temp is pretty constant, after castrol won court battle in 1999 most "synthetics" reformulated to cheaper group III dino oils now LEGALLY called synthetic, prolly same reason "synthetic" factory fills on a new engine is OK since its dino oil and not the slipprier true Group IV-V synthetics


Just about everything in this post is not correct.....

 

[eddy21]

I bought some Maximja motorcycle oil off Ebay once and it had separated .A watery top and goo at the bottom. Tried shaking it up to no effect.

 

[camelCase]

Originally Posted By: benjy
on the early 90's mobil 1 that was prolly a true synthetic which store longer especially when temp is pretty constant, after castrol won court battle in 1999 most "synthetics" reformulated to cheaper group III dino oils now LEGALLY called synthetic, prolly same reason "synthetic" factory fills on a new engine is OK since its dino oil and not the slipprier true Group IV-V synthetics


Fun fact - most "true synthetics" (read: Man-made from fats & acids) are extremely hydroscopic (read: They love to absorb water). The groupIII oils, which are awesome oils even though many people think they are [censored] b/c they aren't "true synthetics" aren't as bad about this.

In layman's terms - a bottle of opened Amsoil (being a high percentage of PAO base stock) will be more likely to absorb water than an opened bottle of dino oil. However - the water should all burn off as soon as the engine is brought to it's >212ºF operating temperature.

 

[camelCase]

Originally Posted By: camelCase
Originally Posted By: benjy
on the early 90's mobil 1 that was prolly a true synthetic which store longer especially when temp is pretty constant, after castrol won court battle in 1999 most "synthetics" reformulated to cheaper group III dino oils now LEGALLY called synthetic, prolly same reason "synthetic" factory fills on a new engine is OK since its dino oil and not the slipprier true Group IV-V synthetics


Fun fact - most "true synthetics" (read: Man-made from fats & acids) are extremely hydroscopic (read: They love to absorb water). The groupIII oils, which are awesome oils even though many people think they are [censored] b/c they aren't "true synthetics" aren't as bad about this.

In layman's terms - a bottle of opened Amsoil (being a high percentage of PAO base stock) will be more likely to absorb water than an opened bottle of dino oil. However - the water should all burn off as soon as the engine is brought to it's >212ºF operating temperature.


EDIT -- Monday morning posting will get me in trouble due to excessive grogginess.. PAO's are not hygroscopic.

 

[wmford23]

Another option is to go back to the manufacturer and get it re-certified if possible.

 

[Ducati996]

No manufacture would ever make a statement of indefinite shelf life.
It would be bad policy & bad business.
If an unrelated failure was to occur the manufacture could end up in court.
I have an old stash of M1 5w40 turbo diesel oil that I’m using, but it’s my call!
Oil is an engineered product that can or could chemically change over time, how long would that take who knows??
If I was to market a product I would put a shelf life on it also for my own protection.

Ducati996

 

[RF Overlord]

I think Ducati996 has hit the nail on the head. No manufacturer will ever tell you their product is good forever...that would limit sales. I'm not saying oil has an indefinite shelf-life, just that any reasonable time should be fine. Quaker State Super Blend in the can was a fine oil at the time...I used to use it...and if I knew its provenance, I might put it in my 1968 Skylark, but let's be real...today's oils are so much better why bother?

FYI, I just put some 8 year-old M1 in my DD, and I'm not concerned.