Originally Posted By: car51
Originally Posted By: Ducked
Originally Posted By: Zee09
Seems Chevron answers this question with their Euro 5W40 Havoline Ultra
Read down to the bottom in the gray box.
60 months from the bottle filling date- Interesting
Its would only be really interesting if it was believable.
So it isn't.
And just how do you know all this Mr. Ducked?
Easy. It isn't believable because I don't believe it.
That's logically this "all" (of which you speak) required to justify my post.
If you were to ask WHY I don't believe it, my reasons would include:-
(a) The (AFAIK complete) lack of ANY evidence, anecdotal or otherwise, to justify such, or any, time limit.
(b) The fairly numerous but scattered (mostly anecdotal) accounts of ancient oil being tested and used with no evidence of abnormality.
(c) Manufactures general record of arbitrary CYA/sales promoting statements in this and other contexts.
(d) The shortness of many of these stated shelf lives relative to the (itself generally understated) service life in an operating engine. This is likely to be given as a year. Less than 5 times longer on the shelf, uncontaminated, at room temperature, in a sealed (though possibly permeable) container, doesn't compute.
For more specific evidence (sort-of) I go to this
http://www.machinerylubrication.com/Read/172/lubricant-storage-life
Its titled "Lubricant Storage Life Limits - Industry Needs a Standard " and it was written, and is sometimes quoted to support shelf lives, though it in fact does the opposite, since if you read it you might reasonably conclude that "industry doesn't need a standard", since they don't appear to have one, nor any basis for one.
Like most "pitches", what it doesn't say is as significant as what it does. There is absolutely no evidence reported here for on-shelf deterioration of motor oils. Instead, its served up as a ready-cooked "given" with a side order of "The sky is falling" Chicken-Little panic salad.
They survey industry recommendations. Table 4 (recommended shelf life for indoor storage at 20C) is especially instructive
Major oil company C: 10-30W Motor Oil (mineral) 1 YEAR
Major oil company C: 10-30W Motor Oil (PAO) 1 YEAR:
Major oil company D: 10-30W Motor Oil (mineral) 1 YEAR
Major oil company D: 10-30W Motor Oil (PAO) 1 YEAR:
Independant oil company B: 10-30W Motor Oil (mineral) Virtually unlimited *
Independant oil company B: 10-30W Motor Oil (PAO) : Virtually unlimited
Independant oil company C: 10-30W Motor Oil (mineral) : Infinite
Independant oil company C: 10-30W Motor Oil (PAO) : Infinite
1 year (!) isn’t very long, and 1 year to infinity is a pretty wide range. I think you could say there's a certain lack of concensus.
IF the 1 year has a basis in fact, it could mean that the major oil companies massive (but of course secret) testing of their latest oils, extending over several decades, has told them that their oil is particularly fragile.
OR it could be that their general knowledge of the chemistry of their product makes them think it might be particularly fragile, though its odd that the PAO, plausibly believed to be more stable in an engine, is just as fragile on the shelf.
OR it could be that they wanted to cover their big fat corporate arse, and pulled the smallest number out of it that they thought they could get away with, assuming no one would notice that it was completely unbelievable.
Perhaps I'm too cynical, but I've found its actually quite difficult to be TOO cynical, and often quite an effort to be cynical enough.
