does oil "expire"

Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
should use or toss ?
It has a datestamp on it from Sep 2009

Was wondering if oil ever "expires" or breaks down on the shelf ?
My son, the chemisty student, said "yeah"....

--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

In article >, pschuman_no5pam_m3
@interserv.com says...
>
> Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
> should use or toss ?
> It has a datestamp on it from Sep 2009
>
> Was wondering if oil ever "expires" or breaks down on the shelf ?
> My son, the chemisty student, said "yeah"....

Additives probably do. Personally I'd use it anyway.

"ps56k" > wrote in message
...
> Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
> should use or toss ?
> It has a datestamp on it from Sep 2009
>
> Was wondering if oil ever "expires" or breaks down on the shelf ?
> My son, the chemisty student, said "yeah"....
>
> --
> / _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
> No Good Deed -
> Goes Unpunished
>

I'd hazard a guess and say that no, it doesn't expire as such. It may well
not meet specifications as time goes on, but the oil itself is pretty old
(couple of million years at least) and the additives are relatively stable
considering what they have to do. And oil dated 2009 isn't that old at
all... I've seen, and used, much older oil!

On 7/22/2011 1:14 PM, ps56k wrote:
> Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
> should use or toss ?
> It has a datestamp on it from Sep 2009
>
> Was wondering if oil ever "expires" or breaks down on the shelf ?
> My son, the chemisty student, said "yeah"....

Only if the bottle is allowed to vent and has been
exposed to high temperatures (80+ F).

Lynn

Lynn McGuire wrote:
> On 7/22/2011 1:14 PM, ps56k wrote:
>> Happen to find an old unopened plastic bottle of 5W30 - was
>> wondering if I should use or toss ?
>> It has a datestamp on it from Sep 2009
>>
>> Was wondering if oil ever "expires" or breaks down on the shelf ?
>> My son, the chemisty student, said "yeah"....
>
> Only if the bottle is allowed to vent and has been
> exposed to high temperatures (80+ F).

Yep. Used to buy a case at a time, usually about a year before it's all used up. Now I buy the big bottles (5qts) and at 6qts per
change it takes a while to use up evertying. Think about how long the stuff stays in warehouses or on store shelves.

--
DougW

"Lynn McGuire" > wrote in message
...
> On 7/22/2011 1:14 PM, ps56k wrote:
>> Happen to find an old unopened plastic bottle of 5W30 - was wondering if
>> I
>> should use or toss ?
>> It has a datestamp on it from Sep 2009
>>
>> Was wondering if oil ever "expires" or breaks down on the shelf ?
>> My son, the chemisty student, said "yeah"....
>
> Only if the bottle is allowed to vent and has been
> exposed to high temperatures (80+ F).
>
> Lynn
>

WTF? Vent? What's that got to do with it--in your engine the oil is
'vented'. High temperatures over 80 F? Goodness, just how hot do you think
oil gets in a running engine.

If you had said high temperatures > 220 F for extended periods of time, I'd
have bought it, but 80?

On 7/22/2011 1:14 PM, ps56k wrote:
> Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
> should use or toss ?
> It has a datestamp on it from Sep 2009
>
> Was wondering if oil ever "expires" or breaks down on the shelf ?
> My son, the chemisty student, said "yeah"....
>

Oil that is exposed to air will slowly catalyze (forms longer chains)
over a long period. Just take a look at the gummy residue on a bearing
from an old electric motor or the inside of a vintage engine. But it
takes a LONG time (years) and only the oil exposed to the air converts.
I have no problem using a quart of 10 year old name brand oil that has
been stored in the factory sealed container for my 4.2L Jeep. I might be
a bit fussier for the Porsche race engine though...........

On 7/23/2011 9:28 AM, RoyJ wrote:
> On 7/22/2011 1:14 PM, ps56k wrote:
>> Happen to find an old unopened plastic bottle of 5W30 - was wondering if I
>> should use or toss ?
>> It has a datestamp on it from Sep 2009
>>
>> Was wondering if oil ever "expires" or breaks down on the shelf ?
>> My son, the chemisty student, said "yeah"....
>>
>
> Oil that is exposed to air will slowly catalyze (forms longer chains) over a long period. Just take a look at the gummy residue on a
> bearing from an old electric motor or the inside of a vintage engine. But it takes a LONG time (years) and only the oil exposed to
> the air converts. I have no problem using a quart of 10 year old name brand oil that has been stored in the factory sealed container
> for my 4.2L Jeep. I might be a bit fussier for the Porsche race engine though...........

What he said.

Plus the light hydrocarbons will vent to atmosphere over
time. I cannot tell you how much the time is but I would
not use any lubricating oil that has been exposed to the
atmosphere for a "while".

Lynn

Here's another follow on question on oil.

My son has a motorcycle,
and his browsing/reading
led him to use "Rotella T6 5w40"
which is a diesel engine oil - for his motorcyle....
Comments indicating it would hold up better in the high revs engine.

SO - how is this diesel Rotella T6 5w40
different than a car engine 5w30 ?
What would happen if you used it in a car engine ?

ps56k wrote:
> Here's another follow on question on oil.
>
> My son has a motorcycle,
> and his browsing/reading
> led him to use "Rotella T6 5w40"
> which is a diesel engine oil - for his motorcyle....
> Comments indicating it would hold up better in the high revs engine.
>
> SO - how is this diesel Rotella T6 5w40
> different than a car engine 5w30 ?
> What would happen if you used it in a car engine ?

Different formula for higher temperatures.
http://en.wikipedia.org/wiki/Motor_oil
Gas engines run a lot cooler than diesel and oil
ratings are based on the temperature band.

--
DougW